Error during the installation of oracle 11gxe
Don't think MCE are certified to run Oracle 11g XE.

Try 


This thread mentions deleting install paths found at

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\Folders


key from the registry. You can try that. As always, ensure you have a working backup before you fiddle with the registry.
Reinstalling SP3