Let me begin by describing the situation and problem, the problem is that the monitor is receiving a signal but its just blank. And which led to this was when i installed an extra 1gig of memory, before this i had a Nvidia Geforce 7800 AGP graphics card running with 256mb of memory. I upgraded to 1 gig and simply just inserted the memory into the correct slot but when i started the computer it came up blank, and after taking it back out the mopnitor still displays a black screen. But right before installing the memory it worked fine, i cant seem to figure it out and any help before taking the plunge and sending it away to a repair shop would be greatly apreciated.