My Windows XP system won't boot. I get a message that says the file system32\config\system is corrupt or missing. Can I fix this?

If you have an Automated System Recovery backup for the system, the first thing to try is to restore that backup and recover the system. To repair manually, start by booting from the XP installation disk. Choose the Recovery Console from the Welcome to Setup screen. Create a temporary directory and copy the files named system, software, sam, security and default from the Windows\System32\config directory to your temporary directory. Type "exit" at the command prompt and restart.

Press F8 as the computer restarts and choose Safe Mode from the boot menu. Open the System Volume Information folder. You may need to adjust your Folder Options to make that folder visible. Locate a recent restore point folder that begins with "_restore..." in the System Volume Information folder and open the Snapshot subfolder. Copy the _REGISTRY* files that match the files you copied earlier to your temporary directory, then rename them to match the names used in the system32\config directory.

Restart the Recovery Console and copy these files into the system32\config directory. Restart again, then run System Restore from the System Tools menu. More details on this procedure are available here.