See http://support.microsoft.com/kb/918165 "Problems in Windows
Explorer or the Windows shell after you install security update
MS06-015".

If you aren't comfortable with editing the Windows registry
yourself, then go to
http://www.kellys-korner-xp.com/xp_tweaks.htm and scroll
down to Item No. 383 "Hewlett-Packard's Share-to-Web software -
Fix".  Download and run the script to automatically modify your
registry as described in KB918165.  You may need to temporarily
disable your antivirus program in order to run the script.

A revised version of the MS06-015 update was released on April 25
that supposedly interacts better with the older HP and nVidia
software.  You can download the revised update from
http://www.microsoft.com/technet/security/bulletin/ms06-015.mspx .