Vista hangs before showing Login-Screen in cold bootups?

[Guest raddy]

System specification

 

Intel P4 3.4Ghz, Asus P5RD2-VM. ATI XPress 200m chipset,

ATI X800 GPU.

 

Running Windows Vista Ultimate, Windows XP SP2 Pro, Opensuse 10.3

 

Windows Vista is mostly locking up in cold bootups.

Windows Vista locking up after finishing progress bar and before login screen.

That is, in black screen that will be shown between Login screen and

Progress bar.

Please kindly gimme a hint or solution.

 

Observation

 

* I tried Low resolution mode, Sometimes will fix it.

* No useful entries in ntbootlog.

* Event logs are not created for that bootup,

* No other OSes, like Winxp, Opensuse emits this problem,

* Locks up after finishing chkdisk (If chkdisk needs to be run)

* Mostly it will boots normally in next reboot.

* Disabled ATI related service