Different websites suddenly get redirected to the same site without my clicking anything, is it a virus?
When I was on penny-arcade.com, latimes.com and my local library website and I went to look at a different window, when I came back the tab had redirected. Looking through my history, it went through three steps. First is a dns host address(Not posting the full thing because I don't know if that will be a vulnerability to my computer), then a http://engine.spotscenered.info address, then the final site that looks like a scam. Is this a virus or just adware? Is it a security vulnerability? Also, how do I stop/remove it from my computer?
Opaite Mbohovái (1)
You may have ad / mal-ware. Further information can be found in the Troubleshoot Firefox issues caused by malware article.
Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.