Quick update..
Disabled graphics card driver, still BSODs.
Tried the repair install but got a BSOD during that process too.
Tried to reinstall VISTA, got a BSOD.
Next job I think is a complete format of hard drive and clean install.
Any suggestions as to why I shouldn't do that?
I have it all backed up now so there's no issue there and I have all the drivers.
I had a look at the debugger and to be honest it looks a bit beyond me.
Thanks again for your help.