Recently my computer has been freezing when opening Internet Explorer. I have tried installing Mozilla Firefox but the computer also freezes upon installation of this software. Scanning the computer with Comodo Anti-Virus and Xoftspy Anti-Spyware has not fixed the problem, nor has Defragmenting the hard drive. The computer is running Windows XP Professional.

From your description of the problem it seems that your computer, and the installation of Windows, has some underlying issues affecting the computer’s stability. As you are having difficulty, both opening Internet Explorer and installing Mozilla Firefox this indicates an issue larger than simply a bug on the computer or misconfiguration. I often see such problems when the installation of Windows is quite old (i.e. it has been quite a while since Windows was originally installed on the machine) as during this period of time many pieces of software have been installed and uninstalled, gradually building-up files on the machine which have not been removed causing the computer to run slower and also exhibit problem signs (such as freezes). This is colloquially referred to as “bit rot” or “software rot” in the IT industry, whereby the performance of a computer slowly degrades over time. Unfortunately there is no easy answer to the question you have asked, as I imagine the root cause is most likely the age of the Windows XP installation on the machine. As such, my suggestion would be to backup any data on the computer that you need to keep and then format the hard drive and conduct a complete reinstallation of Windows XP on the computer. Be aware, this will result in all data on the hard drive being lost (as you are formatting the drive) so it is essential that any data (which may include documents, emails, etc.) are backed-up prior to completing the reinstallation.

If you are not confident with conducting this procedure yourself I suggest that you take the computer to a computer shop for this work. However, beforehand you should prepare a list of the data which you need to have backed-up so the computer shop knows the data they need to save. You should just provide details such as backup all data in your My Documents, backup your Outlook Express email, etc. and the computer shop can then figure out how to backup this data and then put it back onto the computer once Windows has been reinstalled. Providing this list of items to backup is essential and ensures that both the computer shop and you know the data which needs to be backed-up, avoiding any potential miscommunications (which could be serious given the potential for loss of your data).