I think the Trend Micro (Avanquest) Antivirus (Fix-it) is one of the better products out there. Any of them will slow things down as the antivirus and malware data files grow. You could turn off some of the automated services and do them manually but IMHO, it kind of defeats the purpose. Although there are some who will disagree, I strongly advise staying away from Norton. I personally think it's a space and resource hog. I have also used SPYBOT and find it a very dynamic AV/AM program. What's even better, it is free. As with the others, if you want speed, you'll have to turn off some of the automatic detectors. Another word of caution....if you use Outlook, you will find some of the email antivirus programs will cause Outlook to fail when opening and you have to turn off email protection in order to allow Outlook to open. Trend Micro has resolved that problem with their product and I just tested it today and it works!!.

Here is the direct link from AVG on exactly how to upgrade your AVG. As Owbist says do not remove your current version. direct from the FAQ page on AVG "To install AVG 8.0 Free Edition over the current AVG 7.5 Free Edition please proceed as follows: * Download the latest AVG 8.0 Free Edition installation file from our website. * When you are prompted, please do not open this file directly from the Internet, but click the "Save" button and choose a location, where the installation file should be stored (we recommend saving the file to the Desktop). * Reboot your computer. * Close all running applications, locate the downloaded AVG 8.0 Free Edition installation file (it has a four color square icon and its name starts with AVG_...) and launch the installation. * Follow the installation wizard to install the new AVG 8.0 Free Edition(previous version of AVG will be automatically removed during the installation process). * If a restart is required after the initial configuration, please reboot your computer to finish the installation" Here is a link that might be useful: AVG directions on how to upgrade to AVG8

The reason it used to be advised to disable antivirus programs when installing software was to prevent it from interfering. The concept was that something was making changes to the computer and the A/V tried to prevent those changes. With the advent of Windows Vista and UAC, requiring elevation approval for programs to access/change system files this is no longer necessary. There is one time when it is generally still recommended to disable A/V and that is when installing a Service Pack. There are also times when, during malware cleanup, we recommend disabling security programs so they don't interfere with the process. There is a fairly comprehensive article at TSF that covers most programs, linked below. Here is a link that might be useful: How to disable your security applications

Dennis, thanks for a well laid out list of problems. It does help those who feel they can see some or all of your problems. AVG is by far the most popular free anti virus and I doubt that is your issue. I would not remove that one. Spyware Doctor I know nothing about. If you have the original CD or the download stored on your computer you could remove it entirely using the Add/Remove and see if that helps at all. Superantispyware and or Malwarebytes could be alternatives to trying Spybot Search & Destroy. If you use Spybot S&D be sure it is in fact that program and not a sound alike rogue program. Have you ran any cleaners at all? Not registry cleaners but the Disk cleanup in the Accessories/System Tools folder of XP. Try that and a defrag, it will help modestly. Do you have Google or Yahoo toolbars and are they allowed to run in the background? The Google Toolbar has either 3 or 4 entries in your Startup and using your resources. Click Start click Run type msconfig click OK click the Startup tab Now check each of these items and decide if they do in fact need to run. Google each entry before deciding to stop one because if you stop the wrong ones the computer may not start again. If you stop any you need to reboot. During the reboot you will get a dire warning, do not be alarmed, place a check mark not to see it again and continue the booting.