This fix works in windows Vista, not sure about Windows 7:
Click the "start" button, type "CMD" but do not hit enter. CMD should pop up in the programs list, right click "CMD" , then "run as admin". At the prompt, type the following: "bcdedit -set loadoptions \”DDISABLE_INTEGRITY_CHECKS” and press enter. Notice there are 2 D's for disable, this is intentional. Now reboot the PC and see if the error continues.
If that does not work, there is a Driver signature Enforcement override program. I have personally never used it. Maybe someone on the site can shed some light on the program. The site has a detailed step by step, as well. http://www.ngohq.com/home.php?page=dseo
Not quite sure why an LG driver would not be signed. They have the $$$ to pay for certificates.
**Turning of Driver signature enforcement is a security risk. **