I am also having trouble doing a repair install of XP Pro. Full version of XP Pro, only used on initial install. All updates current including SP2, last updates were about a week ago. After the repair install seems to finish and before the system re-boots the following is the error message i get... Error: Setup had problems registering the following OLE control DLL: D:\XPI386\System32\initpki.dll Contact your system administrator, who may provide assistance in diagnosing this problem. *** Warning: Setup failed to remove the product catalog SP2.CAT. *** Error: The signature for Windows XP Professional Upgrade is invalid. The error code is 426. The service has not been started. *** Fatal Error: Setup failed to install the product catalogs. This is a fatal error. The setup log files should contain more information. Is this because of SP2 being installed ? ? And is there a workaround for it. I'd rather not do a clean install at this point if i can help it. Thanx in advance... patio. B)