You have 2 choices.
A. Use some free online virus scanners, (http://housecall.trendmicro.com
) And do that scan also do the Spyware scan (link on that page)
B: Or you can download AVG Free. http://www.free.grisoft.com
Which is brilliant
And Microsoft anti-spyware www.microsoft.com
and on the home page will be a link to download,The Beta Version (Note: You must be running a Geniune version of XP Home)
And You need Ad-aware SE (www.download.com
) (Search for Ad-aware SE) It is free. You might also want Spybot S&D Also from Download.com. And Run all scans.
Hope This helps,