I just discovered my  PC makes abnormal sounds/noise and is not the Audio music speakers       
 

This is not normal noise for sure not PC overheating and PC's BIOS speeds up all fans to protect its bacon, as all do overheated.?
Look for lose parts, if any thing gets loose (screws) it can make noise,
How to find the source of any noise, and why it fails and how to cure it.
Tools: are 1 screw driver to remove side case lid, and cardboard tube (kitchen paper towel tube used) and one good ear.
Does the noise happen even in the BIOS screens?  (hint Windows is not running and even no HDD present in PC)? if yes this is motor noise caused.
The sonic beeper can make huge noise even only in BIOS if the PC is overheating. (or  at any time)
The top 2 causes of noise are FANS bad or HDD bad.

First is my fast  list :  ( the best tactic is stripping any PC down to its lowest minimum configuration)
  • Unplug all USB devices (at any sign of noise ) They hot plug no problems ever. (for sure any external HDD) HDD means hard disk drive and they have motors.
  • Unplug all external speakers, or head phones, of any kind now. (or 3.5mm phone jacks)
  • Remove all CD/DVD (ODD) from the drive tray, for sure if CD is upside, down and then spins forever and endless racket. (even unplug DVD power cable)
  • Turn off the  external monitor screen just in case, (or noisy projectors  )
  • Open case side (desktop or on laptops, huge disassembly) If this scares you, I give up, stop and hit HOME button.
  • If present, remove the PCIe GPU video card if it has fan out it comes , most have fans but not water cooled) (power off first, do not hot plug anything inside any PC)
  • Look and see if wires/cables are hitting fan blades, if yes, use tie wraps and tie  them back out of the way.
  • Unplug any case fans now, (my z270 DIY PC has 5 fans common ) noise gone? now?,  
  • Unplug the CPU fan for 1 minute, ? then put back this cable quickly so the CPU can not overheat. (never run the CPU lacking the heatsink we are just turning off the fan)
  • Unplug HDD power cables, ? oops silent?, yes, bad HDD. My DIY z270 PC has 5 fans. (any can fail at any time in the real world)
  • Unplug CD/DVD/Blu-Ray (ODD) power cable,  (ODD means optical disk drive, of any KIND)
  • I use rubber hose to my ear (or cardboard tube) and put the other end to all things in the PC to find noise in a tiny location and for sure the next line.
  • The beeper. (The sonic alert noise beeper inside  HERE in codes? or in a very odd way, to tell you the PC is overheated.)
  • If PC is gaming grade and the water radiator fan makes excessive noise (not normal) it is bad.
  • At wits end here,  the PSU fan is bad. (I use a hose to my ear trick to find that)


Top noise makers are motor driven fans, hard drives have motor as do DVD drives.
Keep in mind a bad motor that vibrates can in fact cause other things to shake and those things make noise too, called sympathetic vibration.  (only the true source of vibration matters)!
Learn that if  motor goes off balance it shakes like mad, and other parts can rattle in sympathetic ways from it, like a cars license plate loose and rattles only driving the car.
TOOLS: (even DIY made tools)
Tools make the man, tools make the technician, lacking tools and basic skills, will make this harder. 
I own and use a stethoscope for whopping $5. ( I probe all motor driven devices and listen for abnormal noises)
The HDD Bad  and makes NOISE  heard here.?

A rubber hose used works good too, for listening  more close (hose to ear , other end to object of worry)
listen with PC case side removed, at all {fan casings, PSU case, hdd casing, DVD(ODD) casing, and beeper}
Tool trick #2  is take A long screw driver 12" long, handle to ear, tip lands on casings to hear noise. (all mechanics on earth know this basic trick) "Tactic, skill, method, or trick"
An empty kitchen towel card board tube set on to the ear ( can find noise sources too) a free tool.

Warnings:

First off, the only cure for grossly intermittent noises is patience, and keep the left side panel of Desktop open , to catch it.
Never hot swap( hot plug) any cables/ plugs inside any PC, okay?
I wear an ESD wrist grounding strap. (or keep unused hand holding metal grounds inside PC or the casing metal (chassis)
Laptop noise can be hear to find with 35 screws to removel but the HDD usually has access port to listen to it or remove it.

The long story of how to test and all cures to problems related.
 

I hear odd NOISES,  that is  an Abnormal noise?  "rattles, chirps, screams ,squealing , beeps, buzzing, rattles, ok,  you get the idea.."  (or Marty is inside?)
Desktops only covered here  as laptops are very very hard to dismantle and not do huge damage to it. (ribbon cables and the 3 kinds of connectors to them are very high skilled tasks)


The first steps on any PC is to clean first, if the fan is packed in lint not only will it make noise but will, be off balance and even make other things near by rattle.(buzz)
Then the PC overheats for same reasons   AS SEEN HERE.).
NORMAL NOISES HAPPEN FOR SURE A TO HOT PC, JUST LIKE WHEN YOU RUN TO FAST YOU PANT.
MOST PCs made have fans   have BIOS brains that run the FAN, and the PC speeds the fan up when too hot, and makes more noise, this is 100% normal or the PC is filthy.
If a CPU overheats, the fans must spin faster and make more noise this is 100% normal and the BIOS does that  to protect the PC from heat damage.
One cure for that (already PC cleaned of all lint)
PC's can have 2 fans (CPU + PSU) + GPU fans and 1 or more case fans, for sure on high end gaming PC's we  have lots of fans to go fast one MUST BURN lot of heat.
The other top causes of noise are bearings, all MOTORS and  fans have about 2 bearings inside that will fail. (same with
HDD and DVD drives) 
SSD drives have no motor and no bearings and can not fail this way. (same with gum-stick SSD M.2 drives, never a noise there)

Fans
have 5 to 10 year life span, less if on 24/7  and vast failure modes, seen HERE.

The life span is bearing life. (some fans are pure junk, with 1 plastic bushing inside, not dual SST stainless steel roller bearings) You do get what you pay for in fans.

The bad sound has only 5 sources:  (macro thinking, big picture)

  • Old fans can make abnormal noises in all PC's, because the.Bearings and all these reasons in this list.
  • The PCs sonic beeper (BIOS POST error noise make) is beeping or LED BLINK CODE or even 4 LED binary errors, seen in your OEM PC manual get it and read it.RTM
  • WINDOWS, SOUNDS TURNED OFF DO NOT MUTE BIOS BEEPS. (Best is to remove the BIOS beeper ,or if soldered down put tape over its sound port)
  • Some loose metal or plastic, in the PC is vibrating and making noise in sympathetic vibration of say a bad fan OUT OF BALANCE)
  • Anything with a motor inside, fans, HDD, DVD/CD/BR-D drives can make noise, failing or about to fail worse.
Testing with tools and ears and hands:
If you get to  thinking Windows makes this noise (software caused some how) then unplug the SSD or HDD boot data cable, see IT IS NOT A WINDOWS ISSUE.
Go into BIOS screens  page 1,  this is power on hot Key , only covered in you OEM's PC support manual on their web site?
DIY tools:
The Next step testing is I use a card board tube, from an expended roll of  kitchen paper towel ROLL.(for my EAR)
Open the left side of your PCs cases (desktop) with latch or 1/2 screws rear, (per your service manual )The cover is off and now can find the noise maker 10x more easy, no?.

Put one end of the Roll to your ear and listen very near at 1-inch from all fans  PSU rear,, CPU , and  if present GPU fan or at the case fans common on gaming or very fast machines.
If you find a bad fan, try tightening its mounts or screws or if that fails replace it, easy, you found it so fix or replace it.
The Intel fans have this weak as sick cat,  mobo bottom snap mounts that can break. I don't like them I upgrade to Screw mount fans only. (why risk a $300 CPU with $5 fan)
As seen here  this junk  intel fans with the 4 plastic snaps; .
If you look and see the motherboards sonic beeper device, use the same ROLL tube to prove it is the culprit,if yes, then read you service manual and learn what the BEEP errors mean. 
Some DELLs that sonic device even does  a kinda music sound. (and is overheating)
Modern PCs used LED blink codes, and some have 4 LED (Dell Desktop) that have 4 bti binary POST error coded set. (if set) RTM
The BIOS runs this sonic beeper not windows , windows runs audio sounds to real speakers. ( Unplug all speakers first , Desktops)
The beeper is seen here, clear as day.  (only old PC's beep)
My DELL PC the sonic beeper alarm device, buzzes wildly to tell you the PC/CPU is overheating.
The beeper  use a rubber hose or kitchen towel empty tube, held  to one ear and it, and the beeper has many different codes for each type of PC, no 2 the same ,RTM.
 
On modern PCs (above is 10 years old 2009)  The modern  (approx. 2010+)PC has no beeper now, considered now a nuisance. (some brands)
There are more tests to do if the above fails..
Run the PC with the HDD unplugged  (if 2 or more HDD then pull  them 1 by 1, to find the one that is making noise) ( just the power cable pulled (red/yellow wires)

HDD can make noises (it has motor) just before they die or go dead,  most times we call this a crashed HDD.
HDD can do a very load repeating click sounds (bad HDD) not the normal very weak, light ticking sound with ear to case, if you stand say 2 feet away the drive most not click load and fast and endless.
Hard disk drive checks?. (just unplug it , noise gone?,
HDD normal sounds, starting
Unplug the CD / DVD or Blu-Ray drive next,  as those too can  make noise when bad or cracked disks inside.
Make sure the CPU fan is not loose.
Make sure the CPU heat sink is not loose on the CPU,  or MG fell off. (oh my golly) (or eject the tray and see if the DVD drive is now quiet?)
GPU fan, CASE fans bad?
Make sure all screws in the PC are tight. (never loose and rattling about)
Some nice PCs have plastic cooling air baffles in the PC directing cool air over parts,  sure not loose works. (top quality PC have these)
Cables not hitting fan blades  or other things?
One more , could remove the PSU and bench test it for noise.!(and its noisy FAN)
I think I got them all here.?  Bad fans


Fans failure modes all ( gee if it makes bad noises, clean first of the silly dust bunny's  AS SEEN HERE.)  This should be obvious ?
  • Wires in PC hit the fan, so move them out of the way even use 1cent TIE WRAPS and cure that. (even sold at the Dollar store for bag full or at walfart)
  • Bearing shot after 10 years heavy uses.  (sorry chips last 100 year, fans 10, or less ,far less with cheap $1 plastic only bushing bearings.
  • Fan seizing.
  • Fan rattles.
  • Fan wobbles. (even tickling it (no power) with a Q-Tip™ (the rocking tests, by hand to find illegal play)
  • Fan blade missing
  • Fan blade cracked
  • Housing cracked or loose on the mount.
  • Fan blade kissing inside of housing. (See bearing shot)
  • At wits end, have shop find this and fix your PC.
Buy a dual ball bearing fan, steel or SST (stainless steal) not plastic ball bearings(a cute joke from only China) 
Do not spin the fan to 10,000 RPM with  an air hose, or Can-O-air.
Buy fans that are bigger, for Case, (if case as options for that as some do) Huge fans move more air and run slower, and even make way less noise.
Buy fans that have thermal sensors (case fans) if the PC has none, so only makes noise if it MUST with new sensor fans
Buy newer PCs with 4 wire fans, that run super slow (600RPM ) when PC is nice and cool, like when reading EMAIL and not AAA gaming. (the latter will make noise, for self preservation)
If you don't like normal fan noises?, then buy a silent PC or water cooled PC with only fan less cooling towers. seen below.
Many Notepads have no fans or any HDD, but most desktops do,  and some water cooled have just 1 very slow huge turning fan on the radiator.
It is possible to move all the heat out side the PC to towers and other quiet fan based cooling towers.

Silent Gaming (AAA+) PCs are not cheap if silence is your BAG! ($300 kits?)
HDD NOISES good and bad.
Normal Modem noises.

Standing too close to  Matthew Broderick (War-Games 1983')  << 1/2 joking here...



RTM: read the manual at your OEM web site, (Dell.com. HP.com,  Acre.com , Lenovo.com ,etc)

My Jargon page is here.  Like HDD, and SSD, etc.


version 34.  11-11-2019