How to recover from a corrupted registry that prevents Windows XP from starting

The following Microsoft KB article 307545 describes how to recover from a serious system failure, in which a file becomes corrupted and you can no longer boot the system.

KB307545

It's a fairly complicated procedure and you have to be careful if you have an OEM system as you may get stuck at the recovery console password prompt after restoring the files.

"Warning Do not use the procedure that is described in this article if your computer has an OEM-installed operating system. The system hive on OEM installations creates passwords and user accounts that did not exist previously. If you use the procedure that is described in this article, you may not be able to log back into the recovery console to restore the original registry hives."

This is a where a program like ERD Commander (now called Microsoft Diagnostics and Recovery Toolset)comes in very handy. Download a trial version here