Games keep crashing to desktop, help!

[Xeropaladin]

So recently I changed my computer, and after doing so I installed a fresh copy of windows 7, and then installed some of my games to the new comp. I've been trying to play Borderlands and Fallout New Vegas and when playing fallout nv, I start a new game, set all the settings to low, did the starting things at doc's house but as soon as I try to leave doc's house, I crash to desktop. With borderlands I get past the intro's and what not then it crashes to desktop while loading the gameplay.

My specs are

Pentium(R) Dual-Core 2.50GHz
4.00 GB of RAM
Windows 7 Ultimate (64-Bit)
NVIDIA GeForce 7800 GT

Now previously I ran these games on this comp but I only had about 3gb of RAM and my processor was a little slower.. If anyone has suggestions for a fix I'd appreciate it! (Sorry if this isn't the correct forum to post this in, just looking for a fix asap)

[OhpUldum]

Have you installed your motherboard drivers? Have you installed your video card driver?

[Xeropaladin]

I've found the issue, My video card was overheating and so the games would crash to my desktop to prevent my card from blowing up.. a little thermal paste and now all works. Thanks!