Windows 7 - NVIDIA GeForce GT 420M 0x116 stop

When this crash occurs, the screen freezes for about three seconds, after that it goes black for five seconds (more or less) before my laptop reboots, while the audio loops all around. No BSOD to be seen. I'm running Windows 7 Home Premium 64-bit.

It happens when I try to play certain games (it happened for the first time when I tried to play the Planetfall mode for Civilization IV: Beyond the Sword), when I'm watching an online video stream (YouTube and similar sites), or when my computer feels like it (that is to say, randomly).

After some time I managed to narrow this problem down to my graphics card, and to actually identify a stopcode (being a non-expert, this is all rather new to me). This crash didn't occur at all while running Safe Mode, for example.

There is something strange about this, as well. I was trying a solution that remedied 0x116 problems for Vista, and since I was growing desperate, I thought I might try that. It involved renaming nvlddmkm.sys (in Windows\System32\drivers) to nvlddmkm.sys.old, fetching nvlddmkm.sy_ from my NVIDIA folder and copying it to Windows\System32 (which my computer didn't want to do, no matter what, which frustrated me to no end). While I was doing this, I had another system crash like this. It booted perfectly fine. Granted, I couldn't do anything that involved DirectX and my resolution was incredibly low, but I could watch video streams once again, which I couldn't do when the graphics card driver was active.

Naturally, I made sure that I had the latest driver for this card, but that didn't remedy the problem. I had Memtest86+ do two passes, as well as a program that tests video memory, and neither returned a single error.

I'm hoping someone who frequents this forum can help me out. If at all possible, I'm trying to avoid buying a new video card or opening my laptop at all, because the parents aren't at home and won't be for the next couple of days. I don't want to try anything by myself, because I'd likely royally screw it up.

Some specs:

Platform : Intel Calpella
Motherboard : Acer AS5742
Processor : Intel Core i5 460M @ 2533MHz
Physical Memory : 4096MB (2 x 2048 DDR3-SDRAM )

Kind of want help, pretty please?

Test your GPU
Nvidia Video Card - Test with OCCT

STOP 0x116: VIDEO_TDR_ERROR troubleshooting

This BSOD is often caused by defects in the RAM or graphics card

I've already tested RAM and video RAM on two separate nights, and no single error was found. I'll run that GPU test now, though. Thanks for the response!