Problems w/ AdProtect malware ???

In the past 2 wks, I'm seeing an increasingly common problem using FireFox, ie Firefox slows down

& indicates its Not Responding. Then, a dialog box pops up saying that a script on the page has stopped

& do I want to stop it, cancel it or debug the script. The path in the warning mentions that the script is

AdProtect.

How do I safely remove AdProtect from my PC ?? I have no idea how it got there. Thinking its a plugin, I've deleted FireFox

& reinstalled followed by a reboot . That did no good. I have Norton 360 & did a full system scan . Didn't find

anything amiss. Did some googling for the problem. Should I run malware cleanup sw from malwarebytes.org?

I don't know if I'll be making the problem worse. Any guidance/suggestions here will be much appreciated.

Thanks