There are a few good antivirus scanners out there. The one I would recommend is AVG available to download free from here. (serial = 6-XFREE-522613-AVG)

In the space of 7 years I have caught a few viruses, one which was very serious and had to format. The best advice I can give is never download any programs from KaZaA and never open an attachment on emails that you don't know who are from.

If your Internet Explorer homepage has changed and you cannot remove it, then you probably have spyware, click here for more information,

And my last tip is to make sure you keep your antivirus up-to-date as new viruses come out all the time.