I've had the same problem under XP and now under VISTA.

Is your cable the genuine Nokia cable, or like mine a third party one?
Nokia claim that only theirs works (naturally).

There's been a post in the newsgroup (General I think) from someone
with the same problem who used another cable from a friend and it
worked so I'm thinking of getting the genuine Nokia cable and going for
their replacement for the DKU-5 -- CA-42

[url]http://www.nokia.com.au/nokia/0,,37187,00.html[/url]

but check here for the compatibility with your phone -- mine is a 3120

[url]http://www.nokia.com.au/nokia/0,,37420,00.html[/url]

Good luck and do tell me what cable and how you get on.