Help - Muvo2 not seen by WindowsXP

Problems with my Creative Muvo2 4GB:

Recently changed MoBo and now my Muvo will not talk to my PC. It shows up in Device manager but no as a drive in My Computer. It shows in the "Safely Remove Hardware" wizard as well. trouble is that when I try to do so the computer freezes until I disconnect the muvo "unsafely". The same when I try to view "Properties" under device manager. On the few occassions when it has shown up as a drive any attempt to use it has crashed the computer, requiring a reset.

This is what I know:
The Muvo is up-to-date and working. It plays music and connects fine to other PCs.

The USB cable is fine (see above).

My USB ports all work, both off the MoBo and a hub. All my other USB hardware works in every USB socket(mouse, keyboard and modem. I even successfully tried a USB hard drive).

I have the most recent drivers and software for everything, from the BIOS up (it is a new install).

System as below:
AMD64 3500 winchester
MSI K8N Neo4 Platinum MoBo
XFX 6600GT gfx card
1 gig RAM
Audigy 2
2 dvd drives
2 hard drives
Antec Neopower 480W PSU

Any help welcome, this is driving me nuts cos I love my little Muvo!