T41p not booting after changing USB mouse???

[gpvillamil]

I have a T41p connected to a MiniDock II (the one with the separate bricklike power supply and four USB ports).

I recently changed one USB mouse for another. I find that when I boot the system, it gets to the Thinkpad splash screen (the one that offers the BIOS Setup and boot order messages) and hangs. Completely. Can't even access Setup or boot order using Enter or F12.

I tried disconnecting various devices, and found that the system would boot when... I disconnected the mouse. How can this be?

The system has a lot of stuff hanging off the USB ports. Basically:

1. External hard drive (mains-powered)
2. MIDI controller
3. Mouse
4. Powered USB2.0 hub

The hub has connected to it:

5. Memory card reader
6. Printer cable
7. External hard drive (bus-powered)