SpreadTrum SP6820 Drivers error 52 Windows 7
"Windows cannot verify the digital signature for the drivers required for this device. A recent hardware or software change might have installed a file that is signed incorrectly or damaged, or that might be malicious software from an unknown source. (Code 52)"Open CMD and run As Administrators and enter bcdedit /set loadoptions DDISABLE_INTEGRITY_CHECKS then restart your computer.
Before Windows boot logo appear Hit F8 to enter boot menu and get into the Advanced Boot Options menu then Select "Disable Driver Signature Enforcement".
now your drivers problem solved