Get error, "Could not stop McAfee Amti-Malware Core service on Local Computer. Error 5: Access is denied." when try to stop the McShield service.

http://www.pchell.com/virus/uninstallmcafee.shtml

read this through

if it were me I would uninstall McAfee, it is not highly recommended by anyone I know.

once it is removed try a free antivirus, I use MSE, but you have to read the instructions first!

http://www.microsoft.com/en-us/download/details.aspx?id=5201

MSE Download

http://experts.windows.com/w/experts_wiki/89.aspx

MSE installation checklist

If you choose to use Mcafee, download autoruns, which shows what loads at startup and you can disable here.

AUTORUNS

http://technet.microsoft.com/en-us/sysinternals/bb963902    

Above is autoruns for loadup issues

If you still can't find the entry in the registry, download Autoruns.  Let it complete scanning and click the Services tab.  Find the name of the "bad" service in the left column ("Autorun Entry").  Right click and select "Jump to".  You'll go right to the proper entry in the registry to edit it.

I would scrutinise what you have loading on StartUp. You need to see if you have programmes loading during boot process which might be changed to on demand.
With Autoruns you can uncheck an item, which disables it from starting, or you can right click an item and then delete it. If you uncheck you can recheck to re-enable the item. It is a much safer approach than editing the Registry and better than using msconfig.
Another useful feature of the programme is that you can right click an item and select Search Online to get information about the item selected.

When using Autoruns you will need to click on the "Logon" tab to see what is running at start-up.