Despite several attempts listed below certain websites are getting redirected to a certain ad website automatically, out of the blue on linux. When some website starts redirecting to this ad website is not predictable but once it happens it happens again and again. Here is what I did:
Removed all browser plugins, browser directories and the browsers themselves but after a little respite it came back.
Changed the user account, it wasn't seen for sometime but then it came there too.
Scanned the computer with two anti-viruses and two rootkit scanners but they turned up nothing.
Not using a router but an Android portable hotspot, which was scanned by anti-virus and i got nothing there.
Formatted the system and did a complete re-install and it is still happening.
Is it a virus running on another computer or is it just hidden somehow? What is this thing and where is it located?