try this which is located
here
Disable the security warning when installing non-certified application
To disable the security warning when installing a non-certfied application, set:
HKLM\Security\Policies\Policies\0000101a = 1 (DWORD decimal)
To restore the warnings:
HKLM\Security\Policies\Policies\0000101a = 0 (DWORD decimal)
Note that this makes it easier for any malware to install itself