Empty desktop for 10 mns in 4.0 -> blue screen

After upgrading to 4.0 i get an empty desktop for 10 mns, then the question to re-register at microsoft (who thought of this?), after which nothing happens there, after some minutes followed by: not enough virtual mem, at the same time starting a snapshot. Clicking that away (slooow) starts data synchronisation and almost freezes the mac. (24' imac 2008, 4gb, fully updated, winxp, sp3).
The process of parallels does only take 2% of CPU, prl_vm_app 20% of cpu inbetween 11 to 26 threads.
Then a screen (slooowly) appears windows has already been activated? well I haven't. Welcomescreen then, 5 mins waiting, I have to click my account? which was overridden before install, 2 mins, activation-question again, has been activated, which culminats in a blue screen of death.



Now what?

 

The next step is to provide Blues Screen screenshot