I have had the same problem with my Medion Laptop.
Bought it some 20 months ago.
When I decided to put SP2 in it I read the forums and realised that there are problems with the graphics locking up.
I then proceded to update the BIOS as supplied by the Medion site, no problems all went well.
I then put SP2 in and the Laptop worked perfectly for the last 8 months or so.
I have recently been having problems with the PCMCIA card I had installed and I, foolishly, decided to completely rebuild the Laptop.
Now I find that I can load up the XP PRO upto and including SP1 but as soon as I the SP2 it all goes tits up and locks the as the graphics drivers load.
Surely the BIOS flash should still be in the BIOS and therfore it should load SP2 OK now.
I dunno I am totally confused, not to mention a bit miffed, any suggestions from either you or anyone else would be welcome.