STOP 7E error on VISTA SP2 WORKAROUND

My Vista installation on Lenovo SL500 (otherwise a surprisingly fine machine)
repeatedly crashes on Driver Power State Failure BSOD STOP 9F

The fun bit is that when I try to reboot I end up with another BSOD STOP 7E.
This happens after loading CRCDISK.SYS.

However, the following procedure turned out to boot up the system again:

1. Unplug all external harddrives! 
2. Try LAST KNOWN GOOD Configuration (boot -> F8)
3. If that does not boot do a CHKDSK of the Vista drive
4. Try Again.

I did this like > 20 times now and this seems to be a reliable approach.
Would love to find instructions how to identify the faulty driver which causes all this......