so i got xp sp2 disabled sfc and it works fine except now it will not run windows update unless i put the old sfc_os.dll back. when i hacked the sfc_os.dll i didnt have the right version so i used 5.0.2195.7038. when i boot up it says it cant find an ordinal7 in the sfc_os.dll. i also have the sfcdisable registry hack and deleted the contents of the dllcache if i put the old dll back will it re enable sfc? are these errors normal?

Well, considering the one you used was for Windows 2000, I'm not surprised it's misbehaving on XP.

Might be an opportunity to try this:

http://www.msfn.org/board/index.php?showtopic=135082

Non-DLL method of shutting WFP off

but if sfc is disabled and you make your changes to the system folder and then delete the dllcache and replace the original unaltered sfc_os.dll what will it do?