And yet another vista installation problem

okay so I decided to take the jump and try out vista. Still
So the installation went fine, took about three or four hours, got to
the point where windows was starting for the fist time and the endless
cycle of reboots began. After disabling automatic restart, the BSOD
error message read: Session3_Initialization_Failed. Safe mode screen
seems to load but absolutely no programs or anything loads, just a blank
vista screen with a mouse pointer. Did a memory diagnostic, no
problems; tried to do a automatic scan fix, left it running all night,
came back in the morning and it was still running, so no dice there.
Upgrade advisor on didn't indicate any hardware conflict
issues, said my machine was compatible. I don't know...can anybody

Computer specs:
E-Machine T3304
2.3 G AMD Sempron Processor
1.5 Gigs of RAM
GeForce 8400GS NVidia Graphics card