Seems like you may have picked up a virus. If you have antivirus protection, some cannot remove all viruses. Try running this first:http://www.malwarebytes.org/products/malwarebytes_free
You can run the free version and can keep fpr future use, ti will not conflict with other antivirus programs. Download and run the quick scan first and make necessary repairs. You will want to run a full scan, it takes a couple of hours, so, you can wait on that. It also doesn't hurt to have this:http://www.softpedia.com/get/Security/Secure-cleaning/CCleaner.shtml
Again, you can try the free version, if you like it, you can purchase the full version later. Ccleaner has a cleaner and a registry cleaner. Run the cleaner and the registry cleaner. If you have Antivirus protection at this time and are happy with it, make sure that it is operational and up to date. You can set it to run daily, which I recommend, and it can probably be set to run when computer is not active. If you would like suggestions on free Antivirus, let me know.