ok after my last post it has stopped working again, so here is the extensive testing I have done this afternoon, maybe it will help try to resolve the problem:
Unistalled wmp11 and wmp11 runtime and reinstalled wmp11
logged on as admin (worked), user1 (worked), user2 (broke), logged in user1 (worked), restarted did not work for anyone.
Unistalled wmp11 and wmp11 runtime and reinstalled wmp11
logged on as admin (worked), user1 (worked), user2 (worked)
restarted
logged on as user2 (worked), admin (broke)
Unistalled wmp11 and wmp11 runtime and reinstalled wmp11
run as local admin (worked) user2 (worked) admin (worked)
restarted
run as user2 (worked) run as admin (broke), run as local admin (worked)
Unistalled wmp11 and wmp11 runtime and left wmp10 working!!
As you can see from above I cannot see a pattern and this has to be the most random problem I have ever come across in the 10 years I have been in the IT support sector!!!!