I'm having a problem with Vista (a clean install) on an HP xw4300 with 1.5 GB Ram. Video cards are FireGL V3100 and Radeon X1300 (both using WDDM drivers). I'm currently using 3 monitors.
Periodically (4-5 times a day), the start menu crashes and becomes distorted and disfunctional. The only way to resolve this problem, when it occurs, is to restart the Explorer.exe process. While this does resolve the issue for some period of time, it is becoming quite annoying.