My new Microsoft wireless USB mouse prevents my computer from booting up. If I unplug the USB mouse receiver, when the computer is off, the computer will boot normally. After the computer boots up and I plug in the mouse, it works fine. I installed the latest mouse software for my Vista system,... no difference.
Is boot from USB set as an option in the BIOS? Try disabling that in the boot order.
I have also seen a couple of systems that hang on boot when certain USB devices are plugged in even if USB is removed from boot order. System would show a black screen with blinking cursor and would sometimes boot after a long period of time. Never found a solution.