Hi,
System Security 2009 is a rogue security program. And yes, you are right it's malicious software. You have to open Task manager (CTRL+ALT+DEL) or hit Start->Run.. and type taskmgr. If you can't open Task manager, then download and run this file:
http://www.2-spyware.com/download/task-manager-fix.reg
Start Task manager
Click on the Processes tab and find System security or Sustem security 2009 application. Select it and press "End task" button. Then select Processes tab and look for any suspicious processes like 05643921.exe or similar. The full list of files and processes can be found here:
http://www.2-spyware.com/remove-system-security-2009.html
Now, you should be able to run antivirus program or download anti-spyware application if you don't have one.