Recently I bought a new computer, but cannot install any of my games. The first time I installed The Sims the game successfully installed. However, after uninstalling the game and attempting to reinstall The Sims (or any other games or programs, such as World Book Encyclopedia and Tomb Raider 3) the following message appears: ‘C:WINDOWSSYSTEM32AUTOEXEC.NT. This system file is not suitable for running MS-DOS and Microsoft Windows applications’. I found an article related to this error on the Microsoft website, but did not understand how to implement the procedures suggested.

From your description of the problem, I assume the article you were looking at on the Microsoft Website is ‘Error message when you install or start an MS-DOS or 16-bit Windows-based program’ available at support.microsoft.com/kb/324767. While this does deal with the error you are receiving, this does not deal with the exact issue since all the programs you are attempting to install are 32-bit Windows applications (i.e. designed to run through Windows as the operating system). However, this error message does indicate there is something wrong (e.g. corruption) with the AUTOEXEC.NT file.

Most likely, the issue is related to some virus or malware which has installed itself on your computer and has corrupted the AUTOEXEC.NT file. You should first scan your computer for any viruses or malware. Make sure your virus scanner is up-to-date with the latest virus definitions and complete a full system scan. Once the scan has been completed (and you have removed any viruses which may have been detected) you should download Ad-Aware SE Personal Edition (www.lavasoft.de), Spybot Search & Destroy (www.safer-networking.org) and Windows Defender Beta 2 (www.microsoft.com/downloads). These three free utilities will scan your computer for any malware and attempt to remove any which are found. By using these three utilities, you have a good chance of detecting and removing malware found on your computer.

Once the scans are complete and any nasties removed, we need to replace the AUTOEXEC.NT file with a good copy. Fortunately, there is a good copy of this file we can use that is kept in another Windows directory. We first need to enable the viewing of hidden files and folders, so we can see the new AUTOEXEC.NT file. Open Windows Explorer, and go to the ‘Tools’ menu > ‘Folder Options’. In the window that appears, click the ‘View’ tab. Enable the option ‘Show hidden files and folders’. Click OK. We now need to obtain the (new) clean copy of the AUTOEXEC.NT. Navigate to the following directory:
C:WINDOWSREPAIR
Find the file AUTOEXEC.NT then right-click on the file and select ‘Copy’. Now we have the clean copy of the file, we need to replace the corrupt copy in the Windows System directory. Navigate to the following directory:
C:WINDOWSSYSTEM32
Paste the AUTOEXEC.NT (which we just copied) into this directory. A message may appear asking whether you wish to overwrite the AUTOEXEC.NT file already in the directory. You should click Yes, as we are replacing the (existing) corrupt file with a (new) clean copy. Once this is complete, restart Windows and you should be able to install the programs.