Try using Tweak UI, it has an option to rebuild icons in it. Once it's installed, launch it and go to repair in the left side menu. The first thing in the drop down list that comes up on the right should be to rebuild icons. It's a small download, just scroll down about half way and look for TweakUI.exe 147 KB. Part of MS's powertoys for xp.
http://www.microsoft.com/windowsxp/downloads/powertoys/xppowertoys.mspx
http://www.microsoft.com/windowsxp/downloads/powertoys/xppowertoys.mspx