C:\windows\system32\config\system missing or corrupt

Problem: When starting computer (Windows XP Home), the following error message is displayed:

Windows could not start because the following file is missing or corrupt
C:\windows\system32\config\system

You can attempt to repair this file by starting windows setup using the original setup CD-Rom. Select "r" at the first screen to start repair. Do NOT use an OEM "Recovery Disc". Only a valid Windows XP media will work or a disc from the OEM that says "Operating System" may sometimes work depending on how the manufacturer labeled the CD.

Searching the internet, I found several places describing the problem which didn't work for me - in my case, the culprit was bad memory installed.

Links: Windows XP Crashed? Here's Help, Microsoft article Q307545, DriverGuide forum.