Hi Sue
Did the anti-virus software give a name for the virus it had removed (often a filename)? Typing this into Google will often bring up some search results, with useful suggestions for getting rid of it.
On the search results, make sure you only go to links that are reputable anti-virus companies, such as Norton and McAfee (virus writers will often seed the internet with tools that supposedly remove viruses, but actually install something much worse).
In future, it's probably worth creating yourself a new profile (username), and only putting the user in the 'Users' group, rather than it being an admin account (the default when you create the first users on your PC in XP). This would mean that any future malware downloaded has less access to your system. Send me a PM if you want some more advice on doing this.
Hope this helps
Chris Seary
My galleryMy Blog