red popup box (bottom right hand corner) saying my comp' is infected
The exact wording of the popup box would be helpful.
You may see a popup from this area – the System Tray – with WinXP if WinXP has not detected that you have a valid AntiVirus progam on your machine. I can't replicate the warnings you might get without disabling my AV program, and I don't remember the exact wordings of all the possible messages. It may say something to the effect of "you don't have an AntiVirus program," or it may say something like "your AntiVirus definitions are out of date," or it may say "you are at risk for virus infections" or it may say "Your Subscription for Updates of your AntiVirus Program has EXPIRED."
(The last one, I've seen recently on a laptop that sat under the bed for 7 months, and I'm waiting for a CD to update the program I'm using before I register again for update subscriptions.)
If the "red popup" you're getting says that you "are at risk" or "could have a virus" or some other such thing, but doesn't actually say "Virus xxxxxx has been detected on youre machine":
IF YOU ACTUALLY DO HAVE a valid and up-to-date AntiVirus program installed, you can go to Start|Settings|Control Panel. There should be an item on the list that appears called "Security Center." Double-Click it to open it, and click on Virus Protection. This should allow you to select something that resembles "I have a current AntiVirus Program Installed and I cross my heart and hope to die I will keep it up to date and the Microsoft Windows XP Security Center should SHUT UP." (Obviously I don't recall the exact wording of the choice offered.)
Note: If the Security Center DOESN"T APPEAR in control panel, see previous posts above about getting current with WinXP SP2 and critical updates. YOU MUST DO THIS IN ORDER TO USE THE WEB SAFELY.
Note: If you don't have a CURRENT AV program, either get one or get it up to date. (i.e. update your definitions file.) You've said you have Norton – and it actually is pretty good – but make sure you've updated recently.
IFF (that's tek-speak for the logical IF BUT ONLY IF) the popup actually says generically "You have a virus" it is quite likely that you are the victim of malware.
What to do about that is more complicated, so I'll wait for you to tell me at least:
"It really does say I have a virus."
Or better:
Its says "sfvrbltqblr – blpxskkk??!!!" (You fill in the appropriate letter values.)