hi  - i noticed that the original thread was left unresolved...well, after much research i've cracked it.
the problem is to do with virtual drive managers such as deamon tools, nero and alcohol120% etc.
and something to do with a built in service called SPTD...

i had the same problem after upgrading my xp to sp2

below is a link to a prog that disables (not uninstalls) this problem

http://www.duplexsecure.com/downloads

if one doesnt work - try the other

it's good to share!

cheers!!!