PC Security Guardian is a fake Antivirus. This rogue displays fake alerts to scare users. It replaces Best Malware Protection, Internet Security Essentials, Smart Internet Protection 2011, Personal Internet Security 2011, Personal Security Sentinel, Internet Antivirus 2011, Internet Security Suite, Smart Security, My Security Shield, Security Master AV, My Security Engine, Security Guard, CleanUp Antivirus and Security Antivirus (family link)
To register (and help removal), use this code: U2FD-S2LA-H4KA-UEPB
Click on the Help icon, Register Now.
Enter the Serial code and click on Activate Product Key.
If your PC is infected with PC Security Guardian follow Bleeping Computer's removal guide.