Here's one for you... I originally had 2x 256M ram installed on my system and decided I'd like to bump it up to 1G so I purchased a Kingston 512M stick to install in the 3rd slot- it's an AD77 mobo so it only has the 3 slots. The 3 sticks are all PC3200 400DDR. However, now the cpu freezes on the windows xp welcome screen. So I took one of the 256M sticks out and it loads up fine. It also reads there is 768M ram on the system. I've tried putting the sticks in different combinations using the 3 slots but it only ever works if there are 2 sticks installed- adding the 3rd causes it to freeze. The system should support up to 2G ram so I don't know whats going on! Hope someone can help!!!