How long did you let it go before you flipped the hard switch or unplugged the mouse? Are you sure it's just not taking forever?
Reason I ask is ... I have an external USB HDD that slows my boot time down to 2 + minutes if it's plugged in while the computer is booting up, and there's no fix for it. Lot's of complaints about it on Western Digital's web site.
The other similar problem I had was with a USB Wireless Lan stick. After I did a few Microsoft updates, I could only use it in the original USB port it was in while I was doing the update. If I had it in a different USB port while booting, Windows never came up and I had to do a hard reset.
Tried the simple things like a different USB port or seeing if you can uninstall the drivers and reinstall them or a driver update? Tried it in a different PC to see if the problem follows?
Good luck with 'er.