I was upgrading my RAM. It had 256 and i was pputting 512 in. After installing the 512 the system didnt seem to recognise it. So i opened it up again and switched the RAM around. This time the system didnt boot. So i took the new RAM out and switched it back to the original setting. This time the system booted up, all fans came on, HDD gurgled, but no image appeared on the screen, merely a no signal sign. Ive tested it on another monitor, same result. THe only thing i can think of is the gfx card, but i have no way of testing that in my dorm, any ideas?