I cant start the 'Apple Mobile Device Service' in I-tunes

Hey all.... my first post... please be nice !

I have i-tunes vers 8.2.1 with the latest qucktime running on windows xp.

I have my i-phone 3gs 32gig attached and windows recognises it in My Computer as an i-phone with a camera logo. but when i have to manually start i-tunes i get a message 'this i-phone cannot be used because the Apple Mobile Device Service is not started'

I have taken off i-tunes and quicktime several times and re-installed to no avail... also i have tried to re-start the service in start>control panel>admin>services but i get a message ' the apple mobile device service on local computer started then stopped' (btw . i only have 'start' as an option in the services... not stop and restart ).

I cant find out how to restart this service as i think that it is responsible for the problem.. despite re-installing itunes and QT several times.... maybe i have to manually delete a file once i have uninstalled before i have to re-install???

I have had this phone working fine previously on this computer before (desktop) and i have made no software changes since. I have however plugged my phone into my laptop wich uses vista os and it still works with that currently, i havent chosen to sync my music to my laptop as the vast majority of my library is on my desktop, and as far as my understanding goes the i-phone only likes to sync with one library ??!!


PLEASE PLEASE PLEASE HELP ME I wanna play with my toy ! lol

Thanks
Matt Baxter