Windows Explorer Has Stopped Working

i face a problem when openning some folders
when i open a certain folders a message appear " windows explorer has stopped working" then the windows restart
i don't know what to do
i attach the picture of the problem

Does it only happen with media files? Tell us about your computer a little.

Hi..

Download, install, run then update the definitions in a free program called Malwarebytes. Scan the machine and let it remove all it finds. Reboot.

Then open an elevated command prompt. Type the following then press enter:

sfc /scannow

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If still problems, uninstall your current antivirus in safe mode with the tool from here:

AV Uninstallers - Windows 7 Forums

Reboot and install MSE to replace.

it drives me crazy
i have a new problem now
i opened my PC and i found all my programs' files empty
yes empty completely
all the programs gone except the antivirus which is Eset
i do not know what to do
by the way my windows 7 is need to be activated and he want me to change product key and that was from a week
can that be the cause of the program problem??