If you want to find a easy way, the easiest way you can see.
1.Click Computer on your desktable and right click Disk C to select Properties.
2.Click Disk Cleanup, you'll see a window just as right, this process need some minutes.
3.Under Disk Cleanup there are Files to delete, tick the files you don't need to free pc space, finally click OK.
1.Click Startup and type cmd in the searchbox, then double click on cmd.exe.
2.Type gpupdate and press enter, then you can destroy virus on your computer.