I've tried everything!!
Lots of ways, but essentially remove the IDT folder from my 'Programs' folder; then put the new IDT folder in its place (which i got from cnet - still not sure it is the right one as it is not very similar to the one i removed; but the zip file i got from dell appears to be the same as it); the ran the set up file inside. it waits, then gives the message 'ExitError: error device = object not present. restart the system and try again'. of course i have done so, but with no joy.
By googling this message i see people who have had similar problems have ultimately had to reinstall windows from the original disc.
I really really don't want to have to do this. i assume i would have to save all my documents, about 200GB on another disc (would mean buying a hard disc, i suppose); also re-install all my software and settings.
Please somebody tell me there is an alternative to this!!