Web Browsers Freezing Mountain Lion

Question

I upgraded to Mountain Lion over the weekend and I am really beginning to regret it. I went the upgrade route and soon after the upgrade was performed I began to experience system freezes while using Chrome. After a couple freezes I thought it might be best to use Safari. The problem occurred while using Safari as well. To the best of my memory these crashes generally occurred on pages that contained video. I can't say for sure because I may not have reached the bottom of the page before the freeze occurred. I performed a clean install after many freezes but the problem continues.
The freeze begins with a fraction of second where small squares appear on the screen. The screen then freezes but audio continues. During this time I am able to move the mouse but am unable to click on anything. Only option at that point is to use the power button. A crash log is not generated in the diagnostic reports. I'm not sure what is helpful to paste from the system logs but will provide anything you ask for. I'm a reasonably technically literate user but completely new to the support forums as my previous Macs did not have any serious problems.
I am a graphic designer and this is my primary machine and browser crashes are seriously inhibiting my ability to build websites. I would greatly appreciate any advice you can offer.
Below is my system as it is now. Crashes occurred even with a bare bones fresh install.
Hardware Information:
          Mac Pro - model: MacPro5,1
          1 2.8 GHz Quad-Core Intel Xeon CPU: 4 cores
          12 GB RAM
Startup Items:
          tap - Path: /Library/StartupItems/tap
          tun - Path: /Library/StartupItems/tun
System Software:
          OS X 10.8.2 (12C60) - Uptime: 0 days 0:18
Disk Information:
          HL-DT-ST DVD-RW GH61N 
          WDC WD1001FALS-41Y6A0 disk0 : (1 TB)
                    disk0s1 (disk0s1) <not mounted>: 209.7 MB
                    WDC1TB (disk0s2) /: 999.35 GB (416.43 GB free)
                    Recovery HD (disk0s3) <not mounted>: 650 MB
          WDC WD2002FAEX-007BA0 disk2 : (2 TB)
                    disk2s1 (disk2s1) <not mounted>: 209.7 MB
                    WDC2TB-1 (disk2s2) /Volumes/WDC2TB-1: 2 TB (811.36 GB free)
          WDC WD6401AALS-00L3B2 disk3 : (640.14 GB)
                    disk3s1 (disk3s1) <not mounted>: 32 KB
                    WDC640-2 (disk3s3) /Volumes/WDC640-2: 640 GB (332.67 GB free)
          WDC WD6401AALS-00L3B2 disk1 : (640.14 GB)
                    disk1s1 (disk1s1) <not mounted>: 209.7 MB
                    WDC640-1 (disk1s2) /Volumes/WDC640-1: 639.79 GB (202 GB free)
USB Information:
          Logitech USB-PS/2 Optical Mouse
          Apple, Inc Apple Keyboard
          Apple Inc. BRCM2046 Hub
                    Apple Inc. Bluetooth USB Host Controller
          Creative Technology Creative USB Headset
FireWire Information:
Kernel Extensions:
          foo.tun          Version: 1.0
          foo.tap          Version: 1.0
Problem System Launch Daemons:
Problem System Launch Agents:
                 [failed] com.apple.afpstat.plist
Launch Daemons:
                 [loaded] com.adobe.fpsaud.plist
                 [loaded] com.adobe.SwitchBoard.plist
                 [loaded] com.microsoft.office.licensing.helper.plist
Launch Agents:
             [not loaded] com.adobe.AAM.Updater-1.0.plist
                 [loaded] com.extensis.FMCore.plist
User Launch Agents:
                 [loaded] com.google.keystone.agent.plist
User Login Items:
          iTunesHelper
3rd Party Preference Panes:
          Flash Player
Internet Plug-ins:
          AdobePDFViewer.plugin
          Flash Player.plugin
          FlashPlayer-10.6.plugin
          JavaAppletPlugin.plugin
          QuickTime Plugin.plugin
          SharePointBrowserPlugin.plugin
          Silverlight.plugin
User Internet Plug-ins:
Bad Fonts:
          None
Top Processes:
          3.2   %          WindowServer
          0.9   %          EtreCheck
          0.6   %          mds
          0.5   %          fontd
          0.2   %          mdworker
          0.0   %          loginwindow
          0.0   %          Finder
          0.0   %          Dock
          0.0   %          imagent
Video Card:
ATI Radeon HD 5870
(I included this as I have seen other posts connecting this to specific video cards)

Answer 1

VikingOSX
I made a call to Apple Support. We ended up deleting the plugins folder, deleting the cache in the Library and rebooting in safe mode. While in safe mode we reinstalled Flash. After restarting things appear to be running. I ran video from NBA league pass and Netflix while browsing youtube and other video intensive sites. It appears things are running as they should (and I hope this continues). I went 15 mintues without crashing so we'll see if the fix is permanent.
I will answer your questions as this issue still has me concerned and if the info is of any use for you or someone might all the details might as well be on the record.
If you haven't already, use Disk Utility to verify/fix permissions.
Haven't done this yet. May do it anyway.
Boot the Mac Pro into safe mode by holding down the shift key on boot. This will rebuild or repair some stuff, including your font cache.
Had booted in safe mode earlier today and while on the phone with Apple Support. It seems the second try was a charm.
Questions or Observations
If that FlashPlayer-10.6.plugin was older than the current Flash Removal script, it might have remained, before and after your new FlashPlayer install. Remove FlashPlayer-10.6.plugin (again).
I deleted my drive when I installed ML for the second time. Driver should only be from the last few days.
What Graphics Card is installed in your MacPro?
Radeon HD5870 - (I had noticed NVIDIA users had similar problems)
If you run the /Applications/Utilities/System Information.
Selecting Hardware, what is the Boot ROM Version that is reported? If you applied the 2008 Mac Pro EFI firmware update 1.3, you should see a Boot ROM entry of MP31.006C.B05.See here and here for this update. (MP51.007F.B03) Problem?
Selecting memory, does it report “OK” for each bank of memory? Yes
Are you current on your Extensis Font Management software? Is there stated compatibility with Mountain Lion? Yes & Yes - updated Extensis Immediately
You appear to have third party kernel extensions installed. What are these, and if necessary, are they Mountain Lion compatible?
I use a VPN Service and the extensions are required. They are, to the best of my knowledge, ML compatible.
Did your instability problems commence with the addition of the Western Digital WD2002FAEX (disk2) drive? This post on the community might be interesting.
I have had the drive since mid June. It was an RMA for a drive that went bad after 8 months. I have had no problems other than the issue in this thread. Thanks for the heads up though.
Did that Creative Technology Headset require driver installation? No
If this problem resurfaces I will come back to this thread. This issue still concerns me as I feel the whole system should not have been brought down like this. I had maybe 2 or 3 fatal crashes on my G5 quad and this machine in 8 years.
I am grateful for your assistance!