My computer keeps crashing and I'm not sure what's causing it. I have tried everything I can think of. I have reinstalled windows, formated my hard drive, replaced my hard drive, updated bios, and reinstalled drivers, but nothing seems to help. It crashed randomly and for no aparent reason. It locks up completely allowing me to only move the mouse pointer vertically (in this situation the pointer sometimes becomes a square that changes colors). Sometimes it just reboots. One time it crashed leaving me with the blue screen error saying something about ati2dvag driver. I think that my graphics card or its drivers are causing the crashes, but I'm not sure. Please Help.