I have a Dell XPS 435T, 940 @ 2.93 GHz, 6 MB, 64 bit running Vista Home Premium Service Pack 2.
Lately it is taking forever to start or restart.
When starting up most of the time it freezes just after the Windows logo in the center of a black background appears. After aprox 5 min a screen appears reading "Your Computer was Unable to Start". Then "Startup Repair" tries to fix the problem. Many times repair is unsuccessful and I'm offered the choice to use a restore point. Luckily this has always worked.
When I'm restarting the machine, most of the times it freezes on the "Logging Off" screen and I have to manually shut it off.