Start Menu Flicker with 2000 Adv. Server

Installed Windows 2000 Advance Server on a Compaq deskpro with a P/800, 256MB Ram. The start menu and taskbar icons flicker, call compaq and could not support A.S. on this machine. Microsoft's site didn't help much. Does anyone know what the problem could be?? I tried some many possibilities and I still come up dry. If someone can help that would be great...