One of the PC's we have here - an old Dell from around 2002 (I think) is running XP but seems to have slowdown - we think because of a latent virus (or so). I wanted to run a live CD copy of Ubuntu 8.1 that I have lying around to see if it picks up any virus's, how would I? --- I have built http://pcpartpicker.com/p/P5kr - Minus a few parts.
clamtk is what you're looking for, I'm pretty sure it's right in the software manager. That being said, I'd recommend putting Linux Mint on a USB drive instead (using USB Universal Installer), although Ubuntu would probably work well enough for that purpose as well.
Maybe, maybe not. I don't use it, but I've heard that Microsoft's really stepped up their anti-malware game in recent years. I've always just used avast antivirus - its boot time scan is especially useful, assuming the computer is at least in good enough shape to have it installed in the first place.
MSE was great but it has supposedly slipped after it reached the top.
Anyway from my experience the Linux-based ones don't pick up viruses the Windows ones don't, it's that they work when the Windows ones won't. If you get a nasty case of the FBI Virus, just getting into the OS can be a huge pain in the ass. It's much easier to run a live rescue CD and run a scan on the offline Windows partition. --- ---
With a PC that old it'll be easier to just reformat and reinstall everything. That'll help clear out the winrot as well. --- MacBook Pro with Retina Display | 15.4" 2880x1800 | Core i7-3615QM @ 2.3GHz | 8GB DDR3 1600MHz | GT 650M 1GB GDDR5 | 256GB SSD | OSX 10.8.4 | Windows 8 Pro