i have tried to uninstall McAfee from my windows 8 laptop but when I go to uninstall a programme McAfee isn't there as an option although there is a file on the desktop

The file on your desktop could just be an installer for a free trial of McAfee or something like that. If it isn't listed in Programs and Features in Control Panel then it isn't installed. Also, you could try running this uninstaller as well:
http://download.mcafee.com/products...You've been helped by a 15 year old.
If the above doesn't work...revo uninstaller
http://www.revouninstaller.com/revo...
should remove it for you....wise move removing McCrappe.....Some HELP in posting on Computing.net plus free progs and instructions 7 Golds
