Following your advice to another reader about unticking entries in the msconfig start-up list, I attempted the same to make my computer boot faster. However, the next day I found the disabled entries had re-enabled themselves. How can I stop the entries re-enabling themselves? The computer is running Windows XP.

This generally occurs because the process you have disabled is required by another process, and that other process re-enables the process so it can load on startup. When such a dependency exists you should not try to force the process to remain disabled, since it is required for some other purpose by another process. In this situation, you should target the program which is associated with the process rather than the process itself. Since you are trying to prevent particular processes from loading on startup I assume you do not need the function that the process provides. So, perhaps you could uninstall the program or application on your computer which is associated with that process, which should also remove that process (plus any other associated startup processes).

That said, another potential cause is that the process you are disabling is malware (such as spyware or adware) and is being re-enabled by another dependent piece of malware which is installed on the computer (and perhaps hidden from user view). Using Google, search for the name of the process you are attempting to disable. If the process is identified as malware, or cannot be identified (as the process name may be randomly generated to disguise the true nature of the process), I strongly suggest you complete a full scan of your computer using Ad-Aware Free (www.lavasoft.de), Spybot Search & Destroy (www.safer-networking.org), and Windows Defender (www.microsoft.com/downloads) to detect and remove any malware. You should also complete a full virus scan of the computer using your installed virus scanner, or AVG Anti-Virus Free Edition (free.grisoft.com) if you do not have a virus scanner installed on the computer.