USB Causing Crash?

There have now been three occasions (in about as many months) where I place a Motorola Q SmartPhone into it's USB-connected cradle, and the system completely and immediately reboots. Win XP SP3.

Twice now I've not been able to get past the CMOS/BIOS scrolling where I receive the flashing prompt about missing or corrupt file ntfs.sys. Nothing has been able to fix and I've had to restore from a backup image.

This morning I swapped USB ports between the SmartPhone and a Kodak camera dock. When I got home, the system was frozen (as opposed to having rebooted). Maybe a coincidence.

How does one go about finding the source of the problem?

I go to Device Manager and there are a million entries under Universal Serial Bus controllers... Universal Host Controllers, Composite Devices, Root Hubs, etc. Between the USB ports on the ASUS P5K mobo and the Canon printer I have no idea which is which in order to update or check drivers. I currently have no USB card installed but probably will, and that makes the list of USB entries even longer.

TIA for any help.