Try to uninstall your software in the normal manner and reboot the machine. Go to Useful Links a the top of this page and run the MCPR removal tool and reboot again. Login to your online McAfee account and download and install your software and see if this corrects your issue.
If you need further help Technical Support is free and available 24/7
Is this anything to do with Mcafee or a windows issue?
What is the operating system - Windows XP, Windows Vista, or Windows 7?
For Windows 7:
Try to go Control Panel->User Accounts, and change the administrator account's password there; if it asks you for administrator's password, then you will most likely need to restore your laptop to its factory settings either using the recovery partition or recovery media - CDs or DVDs whichever that came with your laptop.