computer randomly reboots

hi,my computer sometimes reboots no matter what im doing on it.it started a few weeks ago so i updated my bios,all windows updates are installed except the optional ones.just yesterday while talking to a friend on facebok,it rebooted.when i look in the event logs,it says something about critical error,kernal something,sytem failed to shutdown properly.any help would be app.is there somwewhere i can look to see what happened,like dumpfiles or some sort of record when it does this?

heres what i got.it accually rebooted just a few minutes ago.it was sitting idle for about 10-15 minutes and just rebooted.

here they are

what does this mean?

should i set mine up like whats in the pic? and where do i go to do this? it could be the bios but it was doing before i updated them,worse accually....what do you suggest i do?i changed the hard disk time thing to never from 20 min.might that be something to do with it?on a side note,very nice and useful programs you gave me to run....

hey np for the late reply,you guys are awsome help.i did that yesterday as i put in my previous post.i had to run out lastnight and do a few things so i left it idle while i was gone and it didnt reboot.not sure if its fixed but im hoping.seemed like as long as the computer was doing something it was fine but when it sat at idle for a while is when it happens.ill keep you posted if it seems to be fixed.thanks again for your great support,glad im here. ;0
as i said i changed it to never but my plan is balanced,is that ok?