ok so i had the same issue with computer stopping on startup
After some trial and error including look for conflict problems, disabling superantispware, disabling functions (none of those ideas worked) i found the answer, at least for me.
ive just found out if stop malwarebytes from loading avast works fine that way too, theres a conflict btwn avast and malwarebytes, but id rather keep malwarebytes and disable avast firewall
to do this method of losing the firewall and keepin malwarebytes
uninstall and reinstall avast dont include the firewall. When it asks u to restart, go ahead. When ur computer is reloaded again make sure firewall is turned off, if firewall is turned on then when u shutdown and then turn on comp the problem will return.
i hope i helped