Boot Problem – XP hangs & can’t stop PM

I started to re-partition a USB HD with PM 6.0 on my XP2003 PC. A bad thing! I have Raid 0 with 2 ATA serial drives. Now I boot and PM won’t let me abort as my keyboard locks nor will the process complete as it doesn’t see the external USB HD. I can get into Recovery console but can’t get Partition Magic not to start at boot_time. I did XP repair install and no luck. What can I do? Any ideas?