Uninstall the McAfee Suite. They probably have an in-depth remover on their web site.
Reboot, then try to make the changes. If it works, you have identified the problem. If not, then it is something else.
You can always re-install McAfee afterwards.
Possibly a simpler solution is to use System Restore to return to before you installed McAfee.
I receive the following error message whenever I make changes to my System Configuration (under msconfig): ?An Access Denied Error was returned while attempting to change a service. You may need to log on using and Administrator account to make the specific changes.?
1) I?m running Windows XP Professional SP2, with all the current updates.
2) I?m the owner/administrator of this computer.
3) Before installing McAfee Security Suite, I never had this problem.
4) I?m currently running McAfee Security Suite (they say the problem is with my OS, not their software).
5) I get the same error message while in ?Safe Mode? ? even using the administrator account.
6) I believe the changes are being applied but the error message is just an inconvenience.
How can this be fixed? Can it be fixed?