Windows 7 “0x0000007F” have been reported on computers with antivirus software installed. In this scenario, you may receive a Stop error message that resembles the following: STOP: 0x0000007F (0x0000008, parameter2, parameter3, parameter4) UNEXPECTED_KERNEL_MODE_TRAP
Do you install AVG free or Zonealarm in your PC? If yes, try to uninstall and put the MS security Essentials.