Windows PC Defender is another rogue antispyware, a clone of OmegaAntivir, Windows Additional Guard, Windows Guard Pro, Ultimate System Guard family fake programs.

Windows PC Defender fake security alerts reads:

“Warning! Your computer is infected
Warning! Trojan Found!
File name: crss.drv
Threat name: Trojan-Spy.HTML.Sunfraud.a”

“System alert
Suspicious software, which may be malicious, has been detected on your PC. Click here to remove this threat immediately with Windows PC Defender”

Windows PC Defender is a scam and must be removed.

Source: http://www.spywares-remove.com/windows-pc-defender