The security shield problem has been discussed here.
http://www.theanswerb.../Question1144153.html
To remove the security shield, you can refer to following steps:
You can download security-shield-killer:http://www.anvisoft.co
m/wiki/security-shield-virus-removal.html
to remove it directly or you can follow alternative way to remove it.
Alternative way to remove security shield:
Step1, Stop its fake alert by activating the fake program with the debugged code, 64C665BE-4DE7-423B-A6B6-BC0172B25DF2;
Step2, Run a full scan with your anti-virus program; If your anti-virus program can't detect the Security Shield virus, I suggest you download Anvi Smart Defender to kill it;
Step3, Restart your computer to completely remove Security Shield virus.