One morning I forgot to disconnect the internet before shutting down the computer. Now whenever the computer starts the following message appears: “Windows could not start because the following file is missing or corrupt: \Windows\system32\config\system. You can attempt to repair this file by starting windows setup using the original set-up CD-ROM. Select R at the first screen to start repair’. I am not able to use the computer in the current state. Can you explain how this problem can be fixed? The computer is running Windows XP.

The message which is appearing on Windows startup is indicating that the Windows Registry has become corrupt. Not disconnecting the internet before shutting down the computer is unlikely to be the cause of this problem, as that would not corrupt the registry to this degree. So something else likely happened. In any case, this is not a good message as the Windows Registry is a core part of the Windows operating system which stores various system and application settings. Without the registry Windows is unable to run, which is why this corruption prevents the computer from working. There is a comprehensive article on Microsoft Knowledge Base dealing with this problem and is available at support.microsoft.com/kb/307545. You will notice that there are two methods available to help guide you through the resolution – guided help or the manual steps. The guided help assumes that you are able to login to your Windows computer. Given the description you have provided of the program I assume that this is not possible, and as such you will need to follow the manual steps. Be aware this is a rather technical process and getting this wrong could cause more problems than it solves. Therefore, if you want to be absolutely certain that this will resolve the problem I would recommend you take the computer to a computer technician. This means that if the problem cannot easily be resolved they should be able to at least recover the data from the computer and do a complete reinstallation of Windows then put your data back on the drive. My only concern with you doing the procedure yourself if you are not comfortable about the process, is that you may not fix the problem and also accidentally remove access to your data on the computer.

Also, note that the Knowledge Base article warns that if your installation of Windows was performed by the manufacturer (OEM) then you should not attempt the procedures. If your computer is a brand-name machine (such as Dell, HP, etc.) then it is likely the manufacturer did a custom installation of the operating system so the procedure in the Knowledge Base article will not work. In this case, you should contact the PC manufacturer for further advice.