The dangers of hot swapping parts           
The word hot does not mean temperature, it means , moving things with power (voltage ) still present.
 Doing so inside any PC, you risk blowing up good GPU cards and RAM or other things inside the PC. (Spark, boom now  a wreck) Can also blow up a good MoBo (motherboard)
This topic is how to service a PC and not blow it up to H3LL.

The PC is not off when turned off  (front button) and also a huge amount of capacitors inside hold a charge for a long time. (even many hours)
The PC is chock-a-block full of large capacitors. (they even ADD UP capacitance.)  See this guy shorting out a cap and learn just how powerful and dangerous it is to hot swapping.
THE CURE IS HERE. (the hard reset)
The chips in all PC have surges protections built in but the above caps charged are a huge risk trusting those protectors. (like jumping off a roof on to your head with crash helmet on)

If you have large batteries in your laptop or notebook that you did not remove first.? BOOM.

The external jacks on your PC can all  be hot swapped, at any time. (a.k.a. hot plug)
Plus Esata jacks of the PC supports it, hot plug. (if does some PCs don't)
My 3 Servers from Dell and HP all have hot swap SAS or SATA bays (designed just for hot swapping)
My Servers have hot swap drives, fans and 2 PSU's  (yes, even 2 PSU's) your PC does NOT have any of this.

The inside, of any standard ATX based,  PC , you must not ever hot swap these devices, and plugs. (jacks)
The huge 24 pin power connector (never hot swap this or its mate the 4 pin CPU power plug, near CPU)
Do not hot swap GPU card cables if seen there, and in the same Vein, do not forget to unlock the card first or the socket will be damage, on any GPU card.
Nor any cable going to the PSU, inside the PC, all of these are RAW DC power rails and most not be connected hot ever.
Do not hot swap anything inside the PC. ( a best practice! ) or you will blow things up, and it can be very costly even $1000 damage. (gaming PCs are expensive)
Never hot swap PCI express slots,  (there are rare exceptions to one this rule on very special made high end PCs or workstations, most folks never seen , much less owned)
All cables inside with multi-colored,  do not hot swap any of those.
Nor hot swap RAM.  (nor CPU, wow)
Nor hot swap SATA drive power cables 15pin or IDE relic 4pins, ever. (yes some server HDD do support this, but not your PC)

The correct action in all cases to prevent the above bad acts.
Is  to do this: See my page called how to HARD power reset this PC (see the section marked SERVICE).
Working inside any PC I wear a real ESD wrist ground strap or I always keep the idle hand touching bar metal, this makes my BODY SAFE from static electric electron discharge. (like seen touching door knob on a super dry day)

Legacy devices long gone that hot swap ok. (or not)
PS2 keyboards and mice (do not do that as many PCs made had no power protection resistor here to make it safe) (one of the top reasons for using USB now as USB is hotswap by design)
RS232 Serial port, (safe even grounding its pins is safe (EIA/TIA rules)
PATA power (never hot swap these) IDE HDD 2001 and older.
Floppy power , 4 pin never.
CD/ BR-d/DVD power , never.

Spec.'s on devices tell what is possible.

The PCI-e spec, covers all this and more, but lets do PCI-express slot, HOT SWAP or HOT PLUG rumors. (PAGE 514+ in the spec, is more clear and the 8 Element rules) << I show this so you know your PC does not have this.

The PURPLE PSU wire is hot all the time, with wall AC power applied to the PCs rear.

A PC plugged in to the wall has power (+5vSTBY) called standby power out of the PSU. At all times plugged into 120vac, (USA) hot AC line power.

The CAPS in any PC love to retain a huge powerful charge, learn to respect them. (as seen here, tortured)

ATX spec  shows the standby power wire pin as purple wire is it, (respect that wire, and win) (pull then AC line to kill standby power dead )

Respect all the Caps in the PC, and many add up to a huge charge and the better the class of Cap, (quality) the longer it lasts.

For the curious what is Latch up ? (and the cause is ESD or users hotswapping parts willy-nilly, devil may care)
  • CMOS latchup via parasitic paths (elements) in all CMOS made chips, the maker works big time to prevent but ESD is huge, some are very fast at over 25000  volt events,
  • The CHIP has a port latchup feature or PORT  CLAMPS, like seen on USB chips and more. This prevents damage to the USB input port . It may latch up and stay that way, until you do the long hard reset stated above link)
  • This port protector feature may lock the port dead, it does this, because it thinks (abstract) that you will hit it again so with more 25,000v hits of ESD or heck more.... This is a feature that is wonderful, self preservation.
  • Some of my personal equipment, I design or modify,   I add TVS and GDT devices to ports that can be hit by ESD. and survive.

Me with PPE on and GOGGLES can take a  huge capacitor the size of water bottle, 47,000 uF, 12v  Power supply connected, I can charge it up and then, short it with a old useless now screwdriver.
It blows the whole end of the screwdriver blade off, gone to metal atoms. (1/4" lost)
Do not do this at home, I have max safety gear PPE here, to do that stunt.
This stunt violates cap. makers spec and damages the cap if done too many times. (have proof, from Nichicon) IT IS A STUNT AND ONLY THAT.
I did this once for  a guy who told me the charge is small  and even after 24 hours rested, BOOM see, CAPS supply almost infinite power at time zero shorted. (physics 101)
The more uF (micro-farads or even Farads and more Volts the more power is stored.
Study how a rail guns work  and learn.

See this link on Kilojoule, can do, see just how powerful stored charges can be,  learn to respect power.

version 3.  2-2-2019