After doing a search (Google or Yahoo), clicking the displayed links takes me to some annoying, generic sales website, from where it is sometimes impossible to go back one page. I have cleared recent history and no chage.
Clicking the links resulting from a search takes me to the same three or four generic site that is tangentially related to the search query.
This happened
Every time Firefox opened
== One month ago?
Wšykne wótegrona (2)
You may have been infected with malware. See What to do when searches take you to the wrong search website
There are a number of search re-direct exploits floating around out there, I suspect you picked some Malware or a Rootkit.
Install, update, and run these programs in this order. They are all free for personal use, but some have limited functionality in the "free mode" - but those are features you really don't need to find and remove the problem that you have. (Not all programs detect the same Malware.)
Malwarebytes' Anti-Malware - http://www.malwarebytes.org/mbam.php SuperAntispyware - http://www.superantispyware.com/ AdAware - http://www.lavasoftusa.com/software/adaware/ Spybot Search & Destroy - http://www.safer-networking.org/en/index.html
If these don't find it or can't clear it, post in one of these forums for specialized malware removal help - or to get information about removing the Rootkit, if that is what is affecting your PC: http://www.spywarewarrior.com/index.php http://forum.aumha.org/ http://www.spywareinfoforum.com/ http://bleepingcomputer.com