I need to repair Windows XP professional, if possible, on my Dell Precision M50 laptop. It had XP service pack 2 installed, and I was trying to upgrade to SP3 but it stopped partway through the installation. Since then it will not start up, reporting that it cannot load hive file because it is either not present or is corrupted. I have tried the sticky: Repairing Windows XP in 8 commands, but it did not solve my problems, though I can get to the Recovery Console.
I would try a repair install with a Microsoft Windows XP CD with SP2, to avoid losing programmes and data, but at the critical stage the repair option is not there. Is there nevertheless some way to do a repair of XP - I would be very happy just to get back to XP SP2.