Re: Thinkpad T61, Odd video and random crashes
Sounds overheated to me, if it gets really hot (laptops do this when playing games), bad things can happen, and the graphics cards on laptops are VERY inadequately cooled. I use my laptop for games, but I always have an external fan and cooling pad in use when doing so. Without them, my 8600M GS reaches 95 degrees C (over 200 F, near boiling point of water) when playing games. I'd recommend taking some desktop case fans and blowing them into your laptop's intake vent, anything to help get the heat off the case will improve cooling.
However, you may have already crossed that point and damaged your hardware. First check RAM, as that can easily be replaced, but if it still has issues, you could have damaged your CPU or GPU.