Under discussion at http://forums.cnet.com/7723-6122_102-511661.html
I have Windows Vista 32bit and just upgraded the ram from 2-1GB DDR2 cards to 4-1GB DDR2 cards. I know that Windows Vista 32bit will only run 3GB but I've read online that the Video Card and other hardware, will also use some memory. So installing 4GB will allow you to use around 3.5GB.
My issue is that when I installed 4GB, the computer would light up like it is on, but the screen would stay black and the tower would beep every 5 seconds or so. It never did start up either. So I removed one of the cards and it works fine on 3-1GB card.
Is the fourth card defective, or the motherboard memory receiver wrecked or can the system not run with more than 3GB installed?