If you don't know how to get into Msconfig.... i doubt whether you have disabled anything in there lol.
I think trying to remove the security center in 'safe mode' is still a good bet.
If the security center is trying to run when you run windows.... that might be the reason you are getting the message 'access is denied'. Running in 'safe mode' should bypass this.
If you need to get into msconfig at anytime.......
Click......
StartClick.......
RunType in....
msconfigClick........
OkThen click on the .....
Startup tab, to see what is running when you boot up your computer.
Untick anything you do not want to run. But don't untick anything unless you are sure exactly what the program is!
Have just come across this.....
Jarra's blogSee if it helps you at all.