Your AV is Anti-Virus (Microsoft Security Essentials MSE for short).
If you already have SuperAntiSpyware then you do not need to download it again just update and run it. If you don't have SAS and instead are using something else then we would have to know the name of it. If you don't have SAS then download the Free version.
When the software is installed on your computer (free versions) restart the computer and select Safe mode, then find the program installed on your system in the Program files list (start menu) and Open/Run it.
Do both programs One at a time so there is no conflict.
After the scan is done (may require a reboot if infection is found but the program will tell you what to do), Open up your browser and in the URL bar (wher you write www.blah blah) type about:config
Then in the Find section just below the URL type search
look through the list and find anything that says websearch, right click the line and select Modify. A box will pop up and ask for you to type a new 'label', delete the websearch 'label' and hit OK.
When you've done that come back for more info (I don't want to give you too much to do in one sitting).