BSOD at boot and shutdown

[cartellinh]

Hello everyone, I'll write here this issue that I cannot solve:
sometimes switching off the computer, it remains stuck in "Shutting down system" page for about 10 minutes and then it shows the bsod screen in the attachment.
About 4 times a month, when switching on, the system remains stuck on Asrock page (before windows boot)
the motherboard is an Asrock H81M-HDS

thanks for the attention

 

[koolkat77]

Configure the system to collect "small memory dumps" following: :ar: http://www.sevenforums.com/tutorials/174459-dump-files-configure-windows-create-bsod.html