Vista Starts in Safe Mode but not normally...

[piano4tay]

I have Vista Home on my laptop and it suddenly crashed & shutdown
today for no apparent reason, It continued to do this when I re-
started, crashing just at the point the sign-on screen appeared.
However, starting in 'safe mode' it works ok. I tried this suggestion:

http://social.answers.microsoft.com/Forums/en-US/vistarepair/thread/392ead6c-71fa-439f-a0ff-9aaa2aec33de

but at Stage 7 it still crashed at startup, leading me to believe that
some Microsoft Service that doesn't load in Safe Mode must be the
culprit.

I tried doing a repair using the Vista installation disk and still the
crash at the Windows logo, and even inserted a Windows 7 disk just for
fun - it loaded the files, but then shutdown just as those cute
Windows & stars appeared....

The only thing I did today which I haven't done for a while is use a
spare power supply (it's generic, but the right spec) since I left my
regular one in the office which I'm out of 'til Wednesday. I noticed
that every time the system crashed the laptop wouldn't start unles I
removed and re-inserted the power cable. But if it's this why would
the machine work in Safe Mode?

I'm completely bewildered what to do next, as even re-installing the
OS doesn't seem to be an option...Any suggestions & I'd be really
grateful...

Thanks in advance!

Mark