'11 MacBook Air Freezing w/Mountain Lion

Question

I have a 2011 MacBook Air (13", 4GB) that was rock solid with Lion for a year. However, ever since upgrading to Mountain Lion, I've been experiencing frequent freezes/lockups.
Sometimes, my Menu bar will freeze, and I'll get the spinning beachball, then the system will completely freeze requiring me to power down.
Other times, the machine will just instantly freeze, requiring a power down.
Still, in another annoying situation, I'll close the lid on my laptop while plugged in, come back a few hours later, and the machine won't wake up. No screen activity, not even any light noticeable through the Apple logo on the back of the screen. NOTHING.
It's getting to be to the point where I don't want to use my MBA anymore and try to do as much work as possible on my iPad.
Nothing has changed software/hardware wise since the upgrade to Mountain Lion. I even tried disabling PowerNap, but that didn't work.

Answer 1

The next time you have the problem, note the exact times when it starts and ends: hour, minute, second.
If you have more than one user account, these instructions must be carried out as an administrator.
Launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Console in the page that opens.
Make sure the title of the Console window is All Messages. If it isn't, select All Messages from the SYSTEM LOG QUERIES menu on the left.
Scroll back in the log to the time you noted above. Post any messages timestamped during that interval – the text, please, not a screenshot.
When posting a log extract, be selective. In most cases, a few dozen lines are more than enough.
PLEASE DO NOT INDISCRIMINATELY DUMP THOUSANDS OF LINES FROM THE LOG INTO A MESSAGE. If you do that, I will not respond.
Important: Some private information, such as your name, may appear in the log. Edit it out by search-and-replace in a text editor before posting.