I think I've been infected with a virus/adware. Every few minutes, on my firefox browser, a new window pops up about some advertisement. I've never clicked anything. Sometimes, i go AFK and leave my browser open and find a few new tabs open. At some times, when I'm searching, I get a new tab with the URL : "http://google.com/webhp" and I've never even went on google.

What I've done:
-Malware Bytes scan(10 times) - No result
-Adaware scan(a few times) - some adware deleted
-Super Anti Spyware scan(Multiple times) - Adware/Trojan/BDT detected, "removed"
-AVG Scan(2 times) - Malware/Trojan, "removed"

I've done multiple scans on multiple scanners, but this virus/adware keeps on coming back. I'm very tired of adware, and this is the best description of the favicon that comes up on each webpage that pops up without my permission: "A vertical grey 'slinky' swirl".

Please help me. I'm tired of having webpages popup with advertisements without my permission.