Strangest problem in windows: even task manger freezing

Hi. I'm hoping someone here can help me. I normally consider myself able to fix problems, software or hardware, and I've built my own PC in the past. However, this new laptop has me stumped. I'd really appreciate any help you can give!

The problem:
Sometimes (probably once every two hours or so of normal use) windows will freeze, leaving me unable to access the task bar, windows menu, explorer (and any folders), and even the task manager. However, applications will continue to run (chrome, AVG, sublime text, etc). Eventually everything will freeze, but it often remains working for long periods of time. A small percentage of the time, I can still access the task manager. When this happens, I've tried killing and restarting explorer without luck. I tried restarting and it froze completely.

I can't pinpoint exactly why/when this happens--sometimes things seem to run fine for several days, then I'll have freezing several times in one day. I may be imagining this, but it does seem to happen more frequently when I switch wifi networks.

Also, some of the crashes have hung on very strange things--once it claimed it was the windows logoff sound that was the file that crashed it! Also, once when I left the computer (letting it put itself to sleep), it bluescreened by itself!

Attempts to solve:
I first thought it might be a virus, but a thorough scan (AVG) didn't turn anything up. Next I suspected that something could be wrong with windows 7 ultimate 64-bit, so I installed a fresh copy. However, this didn't fix anything. Next I checked my HD for errors, but that was fine. I've also made sure that all my drivers are up-to-date. I wanted to update my BIOS, but it seems there isn't a newer driver. Also, running in safe mode doesn't seem to turn up this problem, but it is hard to tell (as the error can take a long time to appear). It seems to happen with regular use, not just being left on.

Since this has happened since I first had the laptop, I think it may be hardware over software.
I've attached the logs on errors (there are a lot!). I uninstalled bonjour recently, as it seemed like it was causing many of the errors in the log, but I doubt that will solve the main problem.

If you need any other info, I'll happily add it. Thanks in advance!

As an experiment, uninstall AVG and install MSE for a while.
You might also want to run an offline scan:
What is Windows Defender Offline?

And see if the info in these two tutorials help:
SFC /SCANNOW Command - System File Checker
Troubleshoot Application Conflicts by Performing a Clean Startup

I ran SFC /scannow, but it didn't seem to find error. Attached is the report.

Also, I will run windows defender offline.

When I had a single core processor I found it useful to launch Task Manager BEFORE any problem.

When Disaster struck the Task manager was already available.
I just had to be patient and wait for Windows to see my finger.
I think a single click required that I hold the button down for a couple of seconds,
and a double click was very difficult to achieve.