The strangest thing is happening: My windows machine will only boot with a USB drive in the USB port. It will boot in safe mode with or without the USB drive. checked bios settings, set to boot only to the SATA HD and shut off booting from USB. This is what happens if I boot without USB drive: first the windows xp screen comes up, then after a few seconds it will go to a black screen and do nothing. Put the USB drive in reboot and it boots with no problems. The only changes I have made are to the GPO settings. could something in the GPO settings be causing this? Thanks!