have you attempted to enter safe mode (tapping f8 when you get to the mobo splash)
if you can get to safe mode it may mean that you have a virus or configuration conflict( 2 real-time avs)
once in safe mode it is possible to check for restore points (remember that the recording of system
changes through system restore is a normal mode function. thus it is not done in safe mode which
is why a system restore is not reversible when done in safe mode.)
if you can recover a working build, you can go to the Toshiba site and download
Toshiba service station which will tell you the serial of your computer.