How do I get rid of an unwanted website

I tried and nothing happened.

I did some searching on the web and found out that "weknow.ac" is a fake web search engine created by a Israel-based developer to extract information from your computer. I found it located in several places of my computer but regardless how I go about removing it nothing happens. Clicking on the item does nothing. I went into "Settings" - "Manage Search Engines" and it shows "www.weknow.ac" as my default search engine although I have all the other popular search engines available. Can't change my default. I also believe that "weknow.ac" is causing "MacKeeper" to appear on my Chrome webr bowser. Can't remove that either.

I HAVE FIXED THE PROBLEM !!!!

Initially went to "Chrome - Settings - Search Engine - Manage Search Engine" and I noticed that I had "www.weknow.ac" as my default search engine. If I clicked on it nothing would happen. If I clicked on any of my other search engine choices I would get a choice of "Edit / Remove From List". I was not able to remove the file "www.weknow.ac" at that time.

I then searched and removed two items that were installed by the Best Buy Apple technician. One was "Flash Player" and the other "Java". I removed both so I don't know which one did the trick.

Next I went back to "Chrome - Settings - Search Engine - Manage Search Engine" and I noticed that now my default search engine was Google. I also noticed that "weknow.ac" had switched position to second on the list. I clicked on it and the "Make Default/Edit/Remove From List" choices opened up. I clicked on remove from list and it did go away. Notice that now I had another choice (Make Default). I then returned to my Chrome opening page and the "MacKeeper" window disappeared and I don't have any "Weknow.ac" files in my computer.

I already have installed "Kaspersky" and it did not report anything out of the ordinary. I removed "Kaspersky". I installed "Malwarebytes" and it states that my computer is clean. I'll try the other 2 but I will have to get rid of whatever I already installed in my computer.

Something new is now happening. If I try to search the web for anything pertaining to malware I get a response that there is no internet connection. I checked modem and it works fine. I can get into Facebook and Apple discussion fine. As soon as I type in either the name of a malware program or "weknow.ac" I get the "There is no internet connection". I think they locked in to my computer.

The following is where I get directed to every time I type any word that pertains to malware, infection, virus, etc.

http://www.trovi.com/Results.aspx?n=569115&q=malware&gd=SY1000390&SearchSource=5 8&UM=8

At the same time I het a notice that there is no internet connection but there is.

So I did some reading and it directed me to System Preferences - Network - Advanced - Proxies - Uncheck all. I only had to uncheck "Web Proxy (HTTP). After doing so I was able to get back to my Chrome web pages. I did not check that off, something else did. I still have the problem with "weknow.ac and MacKeeper".

I failed to mention that the file "weknow.ac" is located in the "Currently Open Websites".

OK, thanks.