I came home to do the malwarebytes as you described (by the way the neighbors told me office depot had installed that and it wouldn't let them update it, but I haven't tried yet).
It might update now that we have got rid of a lot of malware however let's leave that one for now.
The computer was never turned off but I guess it shuts itself down after awhile?
Number of things could have happened. Might have overheated, might have gone into hibernation, might have received some updates and attempted a restart that didn't work or, it might even have been reinfected by a missed, but still active, malware file calling home and downloading some bad stuff.
If it's hibernation, depending on the make and model there will be a simple way to wake it up. On my notebook you press the Fn key and wait. On another of my machines it's the Windows key and on yet another, you just press the start up button once.
I think it's a good idea to shut down a laptop when you aren't using it. That is go to Start > Shut down and log off or what ever you do on that one.
For now though we are faced with the solving the dilemma we find ourselves in.
Some things to try:
Try starting in Safe Mode
Boot into Safe Mode:
1) Restart your computer
2) After hearing your computer beep once during startup, but before the Windows icon appears, tap F8 continually.
3) If you are asked what mode to bootup in press Esc to boot in the default settings
4) Instead of Windows loading as normal, a menu should appear
5) Select the option to run Windows in Safe Mode.
If that doesn't work try a Start up Repair:
Go to Win 7 Startup Repair for instructions on how to carry out a Startup Repair.
If neither of those work, come back and tell me and we will look at another approach.
If one of them does work, please run a FRST scan again and copy and paste the FRST.txt log generated back here.