fu4m13fix2 supports Windows Media Player 11 with IBX up to 11.0.6000.6324 and works with Windows XP, Vista x32/x6.

If your IBX is 11.0.6000.6324 and you receive the following error:
"Failure - Unable to identify RC4 and AES internal keys"
you can:
1. Roll back Windows Media Player to a previous version
2. Install Windows XP (assuming you have your Windows XP install/upgrade disc) on a virtual machine (either VMWare or Microsoft Virtual PC).

Then install lower version of WMP such as WMP 11 beta 2 if required.
After removing DRM from within the Virtual PC you can simply transfer the DRM-free files to your Windows XP/Vista music folder.