Technically, a trojan is not a virus, but like a virus it's a form a malware, meaning it can do something harmful to your computer.
I get those pop-ups now and then, too. If they don't come from your anti-virus program, it's as everyone else is saying - it's probably some company trying to sell you protection or something. IMO, any company trying to sell malware protection by scaring you into thinking you have a trojan is not legit.
I agree, you should run a scan if you're ever in doubt about whether your security has been breached.
Now, there may come a time when your anti-virus program pops up a window saying you have a trojan. If that happens, get the name/number of the trojan, go to the McAfee website, look it up, and follow instructions there for getting rid of it. You may need to download a fix to get rid of it, or reset something. Or your existing software might be able to take care of it, but always check.
Thanks for the vote of confidence, butterflywing!
Just a reminder, if your anti-virus software doesn't update itself automatically, now's a good time to check for updates and even run a full system scan.
I have to confess my eyes popped a bit at first. I thought you were asking about a brand of contraceptives!! :shock: