"windows security alerts 2011" is a probably malware itself or a fake antivirus. This type of malware may have infected your computer through a multitude of avenues including email, and outdated plugins. The video below is "how to" video on removing malware assuming you are on windows.

http://www.youtube.com/watch?v=8Ah3efRdWes&hd=1

Sounds to me as malware as well.

Do a malware check with some malware scanning programs.

You need to scan with all programs because each program detects different malware.
Make sure that you update each program to get the latest version of their databases before doing a scan.

• http://www.malwarebytes.org/mbam.php - Malwarebytes' Anti-Malware
• http://www.superantispyware.com/ - SuperAntispyware
• http://www.microsoft.com/windows/products/winfamily/defender/default.mspx - Windows Defender: Home Page
• http://www.safer-networking.org/en/index.html - Spybot Search & Destroy
• http://www.lavasoft.com/products/ad_aware_free.php - Ad-Aware Free

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

how could it be malware it's my windows center for firewall and virus protection i only dl firefox4 have not receive or opened any emails in the past week and a friend got the same problem from dl firefox4 from their site

thanks for the help though. I can't open programs it says choose program to open with

It's not your actual Windows Security Center, it is a fake program meant to look like it. I found this site very useful in fixing the problem.

http://www.bleepingcomputer.com/virus-removal/remove-win-7-internet-security-2011

I wish I knew how the infection occurred, though.