I take it the computer is not actually BSODing? It almost sounds like a memory error or corruption that is causing windows to freak out?
I take it that you are not overclocking it, this can happen when an overclock is unstable.
It sounds like the VGA is ok if you are getting some sort of start up screen but maybe when the VGA tries to set the resolution that you use for your desktop screen it is somehow not doing it and causing an error.
Its so hard to diagnose especially without any actual memory dumps or BSOD to highlight any issues.
Have you tried safe mode?
It could even be that the system restore hasn't worked correctly, as you know system restore operates on the reboot as well as while restoring, often setting up some files just before you get back into your desktop password screen.
Just come across this which may be of help to yourself?? Startup Repair Infinite Loop Recovery