As above and I'd also off get the following:
Malwarebytes from malwarebytes.org
Install that, update it and run a full scan.
If it finds something then perhaps you need to invest in some other apps to prevent malware getting onto your system.
Run it once a month, update it and perform a scan. Schedule it. Better still buy the full version and have it protecting you 24/7.
Spywareblaster (free) blocks a lot of the holes in the system to stop it coming in, in the first place.
Superantispyware is similar.
If you have an AV program like Nortons/McAfees then consider that its not done its job so maybe its time to find something better (the above 2 have a bad reputation now).
If your popups are purely web browser based then its time for AdAware to be installed, this stops the popups because it knows them from its database so prevents you seeing adverts and popups.
Consider also what web browser you use, Windows Internet Explorer is so full of holes its a joke, try Firefox or Google Chrome or both.