Perhaps you have automatic updates on and installed it again?
Try another tack instead of uninstalling it.
Problems in Windows Explorer or the Windows shell after you install
security update MS06-015 (15 Apr-06)
http://support.microsoft.com/default.aspx/kb/918165
Microsoft Security Bulletin MS06-015
Vulnerability in Windows Explorer Could Allow Remote Code Execution
(908531)
http://www.microsoft.com/technet/security/bulletin/ms06-015.mspx has
been revised to v1.2 to reflect the issues in KB918165.
From the FAQ section:
"On Tuesday, April 25, Microsoft will issue a targeted re-release of
the MS06-015 update."
Now may not be the time to learn Regedit.
I suggest you use a .reg file already done for the purpose.
http://patch-info.de/WinXP/Downloads/KB908531_Share-To-Web.zip
Unzip it, extract the .reg file to a folder, right-click it and select
Merge and confirm when asked.
....Alan