As it is clear that your computer does have virus infections, first thing you must be doing is to do a scan of your computer.
The best software which I can advice is Malwarebyte Antimalware, there is free version of it availiable over internet.
here is the link for downloading the same http://malwarebytes.org/.
download and install it. later do a quick scan and remove all infections that you find using the scan. Then at the end you will get a log about the scan. Please do post that link in order to look in this matter more precisely.
But most of your issues would be fixed with that scan itself,
Also one more suggetion since you are having some website redirections, it might be an issue of "hosts" file corruption.
Some nasty irus do corrupt those files. inorder to give more info on that tell about your computer and also the Operating system that you are using.