Tom had called into our show to say he had been unable to boot to Normal mode, Safe mode, and a command prompt.
Advanced troubleshooting for general startup problems in Windows XP
He might be able to boot into the Recovery Console…
Try to use System Restore…
He might need to try to do a “repair installation”:
How to perform a repair installation of Windows XP if Internet Explorer 7 is installed
How to perform an in-place upgrade (reinstallation) of Windows XP
If you perform an in-place upgrade of Windows XP, all existing restore points are removed and a new system checkpoint restore point is created after the in-place upgrade is complete. Do not perform an in-place upgrade if you may have to use System Restore to restore your computer to a previous state.
If you have Windows XP Service Pack 2 installed on your computer, you must reinstall Service Pack 2 after you reinstall or repair Windows XP…
After you perform an in-place upgrade or repair installation, you must reinstall all updates to Windows…