Hi, I am running a P4 2.53 GHz processor on a ASUS P4PE motherboard, I have 512 of Corsair XMS DDR, and my video card is a POWERED by ATI, 9000 Pro. Everthing was working fine until i recently decided to upgrade my powersupply from 300 Watts to 400 Watts, with a WORKING power supply a friend had given me. It is a generic brand, and everything seems to be getting power. That ATI card has a little fan that spins fine, so I am assuming it is getting power, and yet my monitor just blinks the little green light with no display. I do know that it is connected, because when it is not connected my monitor has a little error message. My monitor is a Samsung 955DF. I have tried the old powersupply to no avail, and various other monitors, i have re seated the card twice and rebooted to many times. Any help would be appreciated.