That raises further questions.
Why?
Did you remove the paste on the stock cooler?
-Yes->Why go through all this trouble?
-No->Found the problem.

Minimum wattage is bullshit, it's massively inflated because some low-end "brands" started to sell e.g. 300W PSUs as 500W PSUs. 270X TDP is 180W, another 80W for the CPU and you've still got plenty to spare.

Case? Airflow you know, pictures would help.

Just to make sure: You didn't apply thermal paste to the CPU in addition to the one that already is on the stock cooler?

Mobo?

Also check the core voltage both in idle and under load.

Still thought the cable length should've been enough to connect both HDD and SSD.

Anyway, since you're crashing in games it's most likely the GPU. My bet is on software. I just wanted to start with what is easiest to check (mobo BIOS version). That leaves us with drivers and GPU BIOS. A couple of 270X shipped with a faulty BIOS, but that was a while ago. Check the driver version first. Especially if you installed the drivers from the CD they might be a bit outdated. Iirc there has been a problem with DirectX 9 applications which fits the issue (only crashing in TF2 and CS:GO) perfectly.

Ok, first things first. I'm not really sure what you mean by "there weren't enough 6-pin ports for the graphic card because I had to use 2 for the hard drive and ssd". Why do you need two 6-pins for the HDD and SSD?

Before we delve into the more interesting possibilities, check the BIOS version. If it's <P1.90 you should update and that might already solve the problem.

#70
They way it looks like right now you can be glad if you get fiber by the time the rest of the world is enjoying their 0ms quantum teleportation 10 Terabit/s connections.

Nah, I'm just curious what you meant with the PSU. I'm 90% sure #13 wanted to know the model/age.
I'd really like to know what "its a desctop pc, so.. ^^" was supposed to mean, that it's got a PSU?

There's nothing to agree or disagree about on the GPU. It's low end and that's it.
http://www.pcgameshardware.de/screenshots/original/2009/09/Risen-HD5850-1920.png
http://anandtech.com/bench/product/1062?vs=1124
If you wish to disagree with benchmarks then suit yourself. What I was trying to say is "Your GPU is shit, the fps you're getting in Risen are normal and you won't get more no matter what you do. Therefore the only problem remaining are your fps drops in TF2 and that could be config related. Since that particular config has never been tested on the exact same hardware because it's a custom config you can't be sure that it's not the culprit."

I'm sorry if stating facts insulted you, but I'm not even trying to offend you. Off the top of my head I can think of 8 11 better ways I could've done so just in these two posts.

And I still want to know about that PSU...

G-Sync isn't all that useful with 144Hz monitors. If you're significantly below 144fps lowering the settings or getting a better GPU would help more and if you're just slightly below 144fps where it's not a problem of low fps but of screen tearing, which is exactly what G-Sync is intended for, you could just lower the refresh rate to 120Hz. I mean it does increase latency (Oh no! The worst case would be a whole 1.3ms if G-Sync added no latency at all! What a tragedy!) on the other hand it's free.

No

EDIT: DAMN YOU BEARODACTYL

Why do you want to avoid rebooting? Are you confusing rebooting and reinstalling or did you never reboot since you got that pc?

About Risen 1: I'm sorry but that's just your GPU being shit.

Just because other people use that config doesn't mean it's good.
Just because it worked on a different pc doesn't mean it's good or will work on this one.
Especially since you wrote it yourself.

I'm not sure what that's supposed to mean.

The VG248QE and the VG278HE are not the same. Different panel size means different panel.

The VG248QE has:
- lower response time

The VG278HE has:
-far better colours (even bigger difference with lightboost)
-better contrast in lightboost
-better gamma
-better brightness uniformity
-better colour homogeneity

I could keep going but I think I've made my point.

Well since you couldn't test your GPU that doesn't tell us much. Could you test the bottom slot with the crappy GPU?

It's not exactly improving your situation if the top slot and your GPU are dead but at least you'd know it's only those two if the crappy GPU works in the bottom slot.

If it's not working either it could be the mobo, cpu, psu or any combination of those and it's not sure your GPU is working either. Once mobo failure is a possibility it gets really difficult if you can't test the components seperately and just sending all of them in for RMA isn't because you don't know which is broken isn't enjoyable either.

tl;dr
crappy GPU in bottom slot
works -> mobo and GPU defective
doesn't work -> check every part on it's own. You'll need help.

Any news on testing your GPU?

If it works I'd test it again with your mobo but in the bottom PCIe slot this time.

Powershell seems unlikely, I doubt you've been messing with individual blocks in the paging file.

I am 99.9% that you don't do maintenance on your hard drive. Random hard drive failures are called random because they can occur at any time for no particular reason. If you want to rule that out simply because it's unlikely I'll apply the same logic to KERNEL_DATA_INPAGE_ERROR: It's unlikely and therefore didn't happen.

Considering it's a SATA II HDD, I'd guess it's pre-2010, max 2011, so it'll probably have 3 (667GB) or 4 platters (500GB). Bonus: 7200rpm. I can definitely think of HDDs that are less likely to fail. You should definitely at least run Chkdsk.

It could also be the RAM. Run memtest86+.

Sidenote: 12GB RAM, possibly 2010 high-end HDD, B75 chipset, GT630 looks a lot like they were just trying to get rid of leftovers from high-end Nehalem systems (the RAM, HDD and maybe PSU (standard 80 PLUs, not even Bronze) and case), got a cheap mobo and GPU and then put an i7 in there to justify a 1000$ price tag. Welcome to the world of pre-builts.

Did that crappy GPU need 6/8 pins?
If so test your GPU in a different pc.

If it works we're down to mobo failure, PSU failure and user failure (aka something's not plugged in correctly).

I take it both the 24pin and 8pin on the mobo are properly connected?