This is a very complicated problem that will probably never get a real solution.
This is going to be a long post. Here's the thing:
My computer freezes when more than 900MB of VRAM (video RAM) is used. The most normal answer would be that this is a bad video card, but I don't think so. You'll see why.
Before I continue, here are some specifications of my computer:
20.0 inch Samsung SyncMaster B2030N
Intel Core 2 Duo E7500 @ 2.93GHz
4GB Unbuffered DIMM DDR3-1333 667MHz
640GB 7200 RPM SATA-II Hard Drive
nVidia GeForce GT610 PCIE 1.1 2GB (manufactured by PointOfView Graphics)
Windows 7 Service Pack 1
Now, this problem happens with any program
while running Windows (will get in detail about that in a little bit). If any program/application uses 900MB of video RAM or more, it'll freeze the computer. Windows will display some artifacts and after a while, this: "The NVIDIA Windows Kernel Mode Driver has stopped working and recovered succesfully". And everything goes back to normal...except sometimes one of the programs may stop functioning properly.
I was a little curious of why this problem was happening, so I decided to use VMST (Video Memory Stress Test) while on Windows, and it was then that I noticed that when it reached/surpassed 900MB of VRAM, it freezes, but VMST doesn't notice anything unusual and will simply say "Test passed!" and countinue on with the testing, which will freeze the computer once again. The only way out is to use Ctrl+Alt+Delete.
Here's the "fun" part of the problem:
-This problem does not happen on Linux with the nVidia drivers installed, although I'm not sure if these were made by nVidia.
-This problem also doesn't happen on the VMST bootable USB disk (you basically install VMST in your USB drive for it to boot up directly after the BIOS). I even tested memtest86+ with a bootable USB, and again nothing happened. All tests were successfull without any weirdness.
-I tried different two different driver versions on Windows to see if the problem went away. First one being the one in the box with the Video Card. Didn't work (in fact, the problem was even worse in this version, permanently freezing Windows!). The most recent driver also didn't solve the issue.
-I thought that the problem would be older drivers that are still being used by Windows somewhere, so I used a program called DriverSweeper, or something of the sort, to completely remove the old drivers (I did some other minor things too). It did remove the drivers, but it didn't solve the problem.
So, for this problem, I can only think of a few answers. None of them have an easy solution.
1. The problem is Windows itself either because of damaged DLL or because of "Windows Rot", so it would be necessary a reinstall.
2. The problem is that Linux and the USB test can't use every resource from the GFX card, while Windows can. This proves the issue is one of the features of the Video Card.
3. The problem is in the drivers, specifically the ones that nVidia provides, which is why this problem doesn't happen on Linux and on the USB drives.
I heavily think that answer 2 is wrong, because Linux still uses more than 900MB regardless. It shouldn't matter what "features are on". The USB thing is even more absurd for obvious reasons.
I don't know if answer 1 would solve this problem, but I'm certain that if it somehow did do it, it would be some obscure DLL/registry conflict no one knows about.
I'm slightly more confident with answer 3. nVidia says that the drivers they provide are generic, and while they should work fine, the recommended version is a personalized one by the manufacturer. The manufacturer's website (PointOfView Graphics), on the other hand, redirects me to the nVidia website when I try to download the drivers. We have a problem here. There is no personalized driver for this video card.
I quite sincerely don't know if there's anything else I should've written here, and I don't know myself if what I'm writing is BS and the reason this is happening is something completely different, but I know one thing: No one I contacted so far was able to even understand what the problem could be. I was only able to say a few thing in IRC here and there. This makes me think that I have quite a...unique problem.
This is the entire problem so far, and the end of this post. Hopefully, everyone understands the horrible phrasing I tend to make in these posts, and hopefully, someone can help me in this weird situation.
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"I'm that guy who runs away successfully, and hasn't watched anime in like forever, I know, I know."--RanAS
Thanks to Rambly, who let me borrow one of their old post layouts.
But fortunately, yet unexpectedly, Shared Memory is now at zero, somehow! 
