Computer kept freezing, decided to reset it, froze when opening browser, no display now

[AccountPlease]

Buckle up, there is a lot to this, more context is best right? (I'll add a tl;dr at the bottom.)

I had a problem recently that my PC would freeze late night when playing games (I figured that meant I needed to let my PC rest and would stop playing) this occured for a few nights.

It would stop my mouse, freeze the display, any audio playing would stop and no matter how long I waited or what I tried (ctrl-alt-delete, alt-tab, win-tab, etc), it wouldnt budge and would always end up with a hard reset.

Then one morning it froze when browsing the web, I tried many different optimization programs (that werent helpful), found a few outdated drivers and installed them (didn't fix it), used CP to test my memory, no errors (my memory has given me problems in the past).

I decided that, its most likely a virus or something related to my hardware and thought that reseting the PC would help or resolve the problem.

However, after the reset, I opened MS Edge and tried to drag the window to the top of the screen to maximize it, it froze mid animation, I hard reset the PC furious that it still persists, but I was disheartened when the PC wouldn't turn on anymore.

I then tried the usual arsenal, reseating memory and Graphics Card, realized it has been awhile since I last cleaned my PC, but I didn't have any compressed air at the moment and decided to wipe everything down with paper towels (got rid of the worst of it at least).

I held the power button when the power cord was unplugged, wiped the heat sink and fan.

I DID NOT WIPE THE BOTTOM OF THE HEATSINK OR TOP OF CPU; it had thermal paste, but again, I didnt have any at hand since I didnt expect any CPU problems and in this case, it's not.

I did however, put the heatsink back on with the old thermal paste, unfortunately.

After cleaning I put everything back together and was hopeful when I plugged everything back in a powered it up, nothing. It turns on, fans spinning, no beeping, however... No display. I checked my graphics card and DVI cord; everything was plugged in and secure.

I again tried to reseat the ram in different slots and even tried one at a time in different slots, neither worked.

HOWEVER, curious about faulty memory, I put my RAM in my mothers PC and I was met with two constant beeps. Ok, I at least understood now. Confident I found the problem, I then tried her RAM in my PC... No beeps or anything, however, no display still. I tried with one stick, different slots, etc, nothing. (Her PC wasn't compatible with my GC, didnt have two open slots for it so I couldnt test that).

I have a two theories;

A). I plugged something in wrong or forgot to plug something in when putting it back together.

B). A different component, aside from the RAM is causing the issue, or a combination of the two.


Specs (off memory since I can't check rn)

Intel i5 8 cores
Radeon 7770
8gb Corsair DDR3 RAM
ADATA SSD (boot drive)
1tb WD blue
ASRock 990FX Extreme3
Cooler Master 500 watt

Tl;dr: Constant freezing, reset pc, Froze again and now wont display, took apart and cleaned, won't display still, reseated and tried different RAM, my RAM got two beeps in moms PC, still no display.

Any and all help is greatly appreciated as I have no clue what in the world is the problem.

However I suspect either PSU or Motherboard.

 

[AccountPlease]

UPDATE: I took apart the entire PC this time, and put everything together again.

PC still has the same problem; meaning faulty part, I suspect the old graphics card is faulty or it could be my DVI wire.

Will be trying a different wire and maybe different GC (unlikely). But I think that is the problem.