why does my firewall keep turning off

It sometimes depends on the security software you have on the computer. If the security software you have has a firewall in it or if you have installed a third party firewall software then you don’t need to have windows firewall turned on. As having two firewall softwares will conflict each other, so to avoid conflicts Windows Firewall will generally turn itself OFF.

But if you are sure that you don’t have any other firewall on the computer then try the following steps:

Method 1:

Check if the windows firewall service is set to automatic

Start -> Run -> type SERVICES.MSC then hit Enter key -> In the Services windows scroll down to findWindows Firewall -> Right Click and click Properties  

Set he “Start up type ” to Automatic and not manual

Method 2:

Start -> Run -> type NETSH FIREWALL RESETand hit Enter

Restart the computer

Also Check: http://support.microsoft.com/kb/283673

<If this post helps to resolve your issue, please click the "Propose as Answer" If you find it helpful , mark it as helpful by clicking on "Vote as Helpful" button at the top of this message. By marking a post as Answered, or Helpful you help others find the answer faster>

Also login to:

http://onecare.live.com/site/en-us/default.htm

And run full system scan, if it is case of Malware then it will detect it and will solve other issue.