Bootcamp does not start

Dear all,

I have just recently installed Parallels on my MBP. After a few problems with the mouse and the keyboard I managed to get Parallels working within Mac OS. The problem now is that I can not start Bootcamp any more. Windows works within OSX 10.5, but if I try to start bootcamp at the startup, it gets stuck during the boot process.
I would be glad, if anybody coud give me some assistance.

Cheers, Jens