Malwarebytes as stated above, also run sbybot search and destroy also free, don't worry to much about the number of threats detected at 537 as most of them will be tracking cookies, not good but will not come to no harm if not slightly intrusive into your browsing habits. If you get some that appear to keep popping up then firstly turn of your windows restore points via the control panel and re scan and get rid of anything and then reboot. If yo can't log into windows as a pop up keep appearing saying you have loads of infections and the only way to get rid is buy the product they offer......DON'T its a scam. just drop me a PM and I will contact you and try to give more help. Top tip download Teamviewer its free for personal use and can let friends get onto your computer and try and fix issues, don't worry its secure and you have to give the person a password to log directly onto your machine. Just very handy when getting other people to help when they don't live down the road. I used to use this when I was an IT tech, but saw the light and gave it all up to drive a van. If I can help please let me know.
cheers
Rick
PS running two anti spyware/malware is fine, but never two antivirus packages at the same time, can cause loads of issues, also never buy antivirus software that you can get for free personal use. most of the free stuff offer paid for upgrade that run all the time but don't bother just use a free antivirus package, and sbybot search and destroy and malwarebytes. Just remember to do a manual scan once a month. and while your there give the hard drive a defrag using defraggler (free) and ccleaner (also free) to clean up old temp and temp internet files etc.