I have used Kaspersky Internet security for several years now and it is very light on CPU usage and I have only once been interrupted by a worm which Kaspersky caught before infection. I used to use Norton's and dumped that hog with a lot of consternation in trying to get it out of the system. I have used spybot in the past and it does a very good job on the malware. Kasperky is not cheap but you can get it for $0 if you look around and get rebates. Another thing I do is ALWAYS get my updates on the OS and related software. Another thing to do is to make sure all the other software on your system is up to date including drivers. For that purpose, I use
Secunia which searches my computer for the software I use including many drivers then advises me of which software needs to be updated and even provides a link to update the software. Have you ever updated your BIOS? The best thing about Secunia is that it is free. Another thing I use to keep my computer running smoothly is cleaning out files no longer needed for that I use
CCleaner. It cleans out all the areas you designate quickly and efficiently. I also use it to manage my startup programs. It has many other useful functions too many to list here. The only thing I shy away from is messing with the Registry with CCleaner. I have done it in the past but that can get you into a deeper mess than just leaving it alone. One thing CCleaner does do very well is tell you errors in registry, i.e. broken links and such. The last thing to keep your computer running smoothly is to do a defrag occasionally. I have mine scheduled to perform on its own. One last thing I do on occasion is to open task manager and look at the processes running. Google the process or find a page that describes the processes to find out what they are (there are many of them out there and you might want to cross check a couple of them). I have found programs I didn't know were running an eating up CPU and/or memory. Many of these programs are installed with other programs when you forget to opt out on the installation. That is where I use CCleaner to inhibit those programs from running on start up.
I'm always looking for helpful hints. Anybody got any?