my iPod won't sync if my printer is plugged in

iTunes 11 (probelm started before update)

Windows 7 64-bit

iPod 5g 80gig

My iPod was not syncing nor being properly recognized by my computer. It was labelled M: drive, but the volume couldn't be opened, and trying to do so would freeze Windows Explorer. I tried all kinds of solutions found on these boards, but I think what worked in the end was that I formatted the iPod on another computer (which did not have iTunes) and restored factory defaults, then I manually located the proper driver on my computer. At that point, Windows recognized the iPod as an iPod, but it still wasn't showing up in iTunes. Finally, I tried unplugging my printer (an HP Laserjet p1102w) because it was the only USB device I could unplug without moving heavy furniture. Amazingly, that worked and I'm back in business after 18 hours of troubleshooting. Yay!

Now I'm trying to figure out why my printer is keeping my ipod from being seen by iTunes. Any ideas? I've checked over and over -- the iPod definitely can't be seen by iTunes if the printer is plugged in. I could work around this forever, but if there's a solution I'd love to figure it out.

Hope someone can solve the mystery!

Thanks,

Melissa