I hated Security center when I got vista...did a little research and the following steps will rid you of those very annoying pop ups security center generates...I've had no trouble after the changes...I use symantec endpoint protection anyway,which is way better...any way here's how: Administrator account has to be used to do this:
To activate Administrator account in Vista type the following from the command prompt,in the root directory...C:\

Net user administrator /active:yes
To turn it off again type:
Net user administrator /active:no

once you activate the administrator account...boot into safe mode...log on with administrator account,then go to windows\system 32 and rename
the following files:
wscapi.dll
wscsvc.dll
wscui.cpl

Change them to the following:
wscapi.dll.bak
wscsvc.dll.bak
wscui.cpl.bak

and reboot...and you'll never see another Security Center pop up...


This is intended for those who want to get it rid of and find it as annoying as I did...