Bungler

Here is a bit more information on the registry and system restore:

When WinXP is installed, the initial registry files are stored in the folder \WINDOWS\repair. The five major files are named default, sam, security, software and system. These files are used when a repair install is carried out using the WinXP CD, hence the need to apply any subsequent Service Packs and/or hotfixes.

The current registry files are located in \WINDOWS\system32\config. It is this version of the registry that is loaded when the computer is booted. If one of the files becomes corrupted the computer cannot be booted, even in safe mode. The solution is to return to a previous point in time via System Restore but using a third-party program as the recovery console doesn’t allow it (Vista does) or running a repair install back to the time of the original installation using the WinXP CD (the \repair folder above).

System Restore points contain older versions of the registry. These are located in \System Volume Information and are stored in a different way. Other backed up information is also stored here.