WinSurf is a Trojan also known as Trojan.Win32.SystemCrash. This Trojan shows fake security messages after user installs fake video codec like Video ActiveX Codec but this is not codec this is just a Trojan zlob. Hakers use this fake Trojan messages to promote Rogue Anti-Spyware applications like Malware Bell 3.2, Files secure or IE Defender. Winsurf usually hides under a dll file winsurf.dll.
For a more detailed description please refer to Trojan.Win32.SystemCrash description.