Follow
these instructions to troubleshoot the connection. It may help to download and install the latest hp drivers if this problem recently appeared for no reason...
If this is a new installation, you have to follow the HP procedures to make sure you only hook up the USB cable when prompted by the software, or the installation will fail. See
this article for xp,
this one for vista installation instructions.
I hope this information allows you to resolve this issue. If you need further assistance, please post back with a comment to this thread.
If I've managed to answer your question or solve a problem, please take just a moment to rate this post....thanks!