I have been given a Sony Vaio 300GB HD and 2GB mem that's seemingly riddled with viruses because the "Rundll32 stopped working" box keeps popping up, the screen resolution changes, it sometimes shuts down to prevent complete failure and the AV software is a trial version which has identified forty-something viruses, trojans etc but which won't fix them without going online to register. I don't want to go online and register it if I can alternatively load Linux and dump Windows. Can I use a CD version of Linux whilst dumping Windows to create a new, virus free OS? From a technical point of view, is there any problem with doing that as a way to eliminate the viruses, or should I try to repair Windows and keep it whilst also loading Linux? It's probably obvious that I'm completely out of my depth with this, but I thought that since the OS is already useless I might as well change the operating system to one that I'm more sympathetic to.

of course you can, installing linux requires you either resize your windows partition first or format over it
all you have to do is download an iso (which can be found on this site by clicking on "download linux" or go to iso.linuxquestions.org then burn it, reboot from the cd and follow the installation instructions

What do you want?

Do you want and need a Windows operating system for some reason? You can probably clean Vista of most of its infections and reinstall it from its restore partition and have it work. You can start by downloading the free.version of AVG antivirus to replace the program that is not active.

Have you googled the model number of you Vaio with linux to see if this machine is well suited for linux or has devices that present problems? You can also do a test by downloading and burning one or more live-cds and booting them to test the system for function. Here is the standard list.

http://www.livecdlist.com/

Burn the download as an ISO image file at a low speed on a good quality cd, and use the key for a one-time boot that you will see when the systems does its POST to boot from the CD drive.

If you are to keep Vista, you may also install linux along with it as a dual boot. If you format all of the HDD for linux, you will have eliminated all threats of a virus. You have a number of choices open to you. Good Luck