PF usage high than usual

If you PF usage, the one possibility that is you computer has infected with worm.I am so lucky that I noticed that there something wrong with my notebook.Worm I 'get' is one that put explorer.exe in system32.I detected it is worm because.This 'explorer.exe' is hidden files.Explorer.exe suppose to be in systemroot:/Windows.Other than that location,that explorer.exe suppose to be dangerous.

To remove that explorer.exe:
1.End task the current explorer.exe
2.Delete the explorer.exe