I think i'm having kind of a similar problem. I just got this back from the after-sales service, and it worked fine for like.. 20min before the screen started flashing and then turned into a mixture of colors.
Before taking this to the after-sales service i got that screen with stripes and mixed colors right after turning the computer on, but now the screen stays normal until the moment windows logon screen should appear.
Now i'm also able to get into windows in fail-safe mode, and after removing my graphics card drivers i can get into windows in normal mode, but the crashing begins again in case i install any new drivers for my graphics card.
Broken graphics card? (as the problems appear apparently when the computer tries to start using the 3d-stuff on the card)
Using fujitsu-siemens m3438g (geforce 6800go)