XP wont boot/install with my new HD3870X2

[oc_junkY]

Hello guys,

i got my new Saphire HD3870X2 this morning.
I removed the Nvidia Drivers, shut down my PC, replaced my old with my new GPU, booted --> XP froze at the login screen.
Booted my Test XP on my Test HDD and it was the same thing.
Installed Vista on my Test HDD --> Everything works perfectly.
I wanted to reinstall XP on my Raid0, but it gives me no chance.
It freezes everytime you have have the choice to press "Enter" for installation, "R" for recovery or "F3" to abort the setup.

I don't know what to do, does anyone have an idea?


Edit: I just have tested Vista CE which works, but UltimateBootCDforWindows gives me a freeze as soon the Windows GUI appears :-(