How do I delete System Security?

Why can't I delete some Folders, and why am I getting strange event logs?

• I noticed a folder in my C:\ Directory, and it said it required permission from SYSTEM to make changes to it. Unknowingly, I decided to remove SYSTEM from the User Group which has permission to the folder. How am I supposed to delete the Folder? I checked the Event Logs on my Computer, and on the exact date and time the Folder was modified, the Event Logs said "Beginning a Windows Installer transaction". I checked my Firewall, to see if the Firewall could have prevented protection from Hackers, Viruses, etc., and I saw that the Firewall didn't have Recommended Settings on. So I decided to change them back to the recommended settings. When I clicked on the Button to change them back, the settings wouldn't change, and I got an error message. I checked my System and Security tab in my Control Panel, and I found that the Windows Security Center Service was turned off! I tried to turn it back on, but I got an error message, saying "The Windows Security Center service can't be started." Do these events have anything to do with eachother? Was I hacked (I got a virus a few months ago. Geek Squad fixed it up.)? And what's the best route for me to take? Should I send it to get fixed? Or should I try to solve this thing by myself? Please, someone answer... In layman's terms. I don't know about commands in the cmd prompt...

• Answer:

  i think this is a virus called autorun,you can download AVG ANTIVIRUS,and do complete scan for ur computer this will take a few time but its good antivirus it work for me good. good luck