What exactly do you mean when you say it goes on tilt? Have you tried putting it into safe mode and then scanning? Hit the Windows Key+S and type in msconfig and hit enter, a windows should come up and you should see a tab that is called boot and in that menu you will see where it says safe mode, put a check next to that and a check next to networking, then reboot your PC, after it boots up then run virus scan, i would suggest Malwarebytes Anti-Malware, and Adware Cleaner called ADW you can also get Malwarebytes from bleepingcomputer.com , Link:
http://www.bleepingcomputer.com/download...
bleeping computer is an valuable tool when having PC problems, but to be honest the first thing i do when my PC is having an issue of running slow or freezing i always check the HDD first, use a program call crystal disk, Link:
http://crystalmark.info/software/Crystal...
Also another nice thing about windows 8 is they have a feature called refresh or reset your PC, if you are really just tired of smashing your head into it and nothing is working, you might try these alternatives, just hit Windows Key+S , and type in refresh and it should come up in the search selections