package shim-signed 1.28~16.04.1+0.9+1474479173.6c180c6-1ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[shivam pandey]

the system is running very slow,
i have dual boot the system
running windowa and ubuntu both.
their is a problem with the wifi driver.
it automatically get disconnected after some time.
if i try to update the system or install any software the system crashes i.e it hangs!!

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: shim-signed 1.28~16.04.1+0.9+1474479173.6c180c6-1ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-78.99-generic 4.4.62
Uname: Linux 4.4.0-78-generic x86_64
NonfreeKernelModules: wl
.proc.sys.kernel.moksbstate_disabled: 0
.sys.firmware.efi.efivars.MokSBStateRT-605dab50-e046-4300-abb6-3dd810dd8b23: