Case 1: This happens due to missing or corrupt SharedAccess registry key, which represents the Windows Firewall Service. This usually occurs if the system is infested with Virus or other Malware, or in the aftermath of Virus removal. In conjunction with the solution provided in the article, it's advisable to run a thorough cleanup of the system.
Case 2: You have Windows Live OneCare installed. Windows Live OneCare has its own Firewall which monitors both Inbound and outbound connections. Because two firewalls should not be turned on at the same time, Windows Live OneCare turns off Windows Firewall if the latter is running. [More info]
Therefore, Windows Live OneCare users can safely ignore the error message concerning the Windows Firewall.
If you don't have Windows live One Care follow the directions below.
Install Super Antispyware. Run it in safe mode. Allow it to quarantine whatever it finds. http://www.superantispyware.com/
Run the online scan for Bit Defender in normal mode. Allow it to quarantine whatever it finds.http://www.bitdefender.com/scan8/ie.html
Post a Hijack This log in the appropriate forum by following the directions in the link below.http://www.bleepingcomputer.com/forums/t/34773/preparation-guide-for-use-before-using-malware-removal-tools-and-requesting-help/