My Macbook Pro keeps freezing/crashing after a few seconds of use, but works fine in safe mode.

Question

I've researched this extensively, but I haven't been able to solve my problem yet.
It started completely out of the blue with a kernel panic, where my screen seemed to malfunction and I got the kernel panic message (but I could hardly read it because of distorted graphics). I forced my laptop to shut down, but every time I rebooted and used it again it would completely freeze after a while (the amount of time varied, it has lasted from a few seconds to a couple of hours). What happens essentially is that the cursor and entire OS freezes, and I'm unable to click on anything or use the keyboard. The fans start working full speed and the only thing I can do is force the laptop to shut down.
At first I thought it was a Chrome problem because it only happened after I opened the browser. After uninstalling it, the laptop seemed to work fine for a couple of hours, but then it froze again while I was using Safari. Ever since it has been functioning normally for smaller and smaller time periods before freezing again. I've tried reinstalling Snow Leopard OS from the original disc and then downloading all software updates, but the problem continues. I've also tried doing a hardware test by pressing D as the computer starts up, but for some reason it doesn't work.
The laptop, including Chrome and Safari, works fine in safe mode.
I'm sorry I don't know what specific information to give you about my laptop/OS, but please ask anything you need to know. I'd greatly appreciate any help — I'm panicking because I fly to England tomorrow morning to start university and I really don't want to go without a laptop for 2 weeks while it's getting fixed!

Answer 1

Thanks for your reply! Here are the Etrecheck results.
Hardware Information:
          MacBook Pro (15-inch, Early 2011)
          MacBook Pro - model: MacBookPro8,2
          1 2 GHz Intel Core i7 CPU: 4 cores
          4 GB RAM
Video Information:
          AMD Radeon HD 6490M - VRAM: 256 MB
          Intel HD Graphics 3000 - VRAM: 384 MB
System Software:
          Mac OS X 10.6.8 (10K549) - Uptime: 0 days 0:51:36
Disk Information:
          ST9500325ASG disk0 : (465.76 GB)
                    (null) (disk0s1) <not mounted>: 200 MB
                    Macintosh HD (disk0s2) /: 465.44 GB (339.98 GB free)
          MATSHITADVD-R   UJ-898 
USB Information:
          Apple Inc. FaceTime HD Camera (Built-in)
          Apple Inc. BRCM2070 Hub
                    Apple Inc. Bluetooth USB Host Controller
          Apple Inc. Apple Internal Keyboard / Trackpad
          Apple Computer, Inc. IR Receiver
FireWire Information:
Thunderbolt Information:
          Apple, Inc. MacBook Pro
Kernel Extensions:
Problem System Launch Daemons:
          [not loaded] org.samba.winbindd.plist
Problem System Launch Agents:
          [failed] com.apple.Kerberos.renew.plist
Launch Daemons:
          [not loaded] com.adobe.fpsaud.plist
          [not loaded] com.google.keystone.daemon.plist
          [not loaded] com.microsoft.office.licensing.helper.plist
Launch Agents:
          [not loaded] com.adobe.AAM.Updater-1.0.plist
          [not loaded] com.divx.dms.agent.plist
          [not loaded] com.divx.update.agent.plist
          [not loaded] com.google.keystone.agent.plist
          [not loaded] com.hp.devicemonitor.plist
          [not loaded] com.hp.messagecenter.launcher.plist
          [not loaded] com.quark.quarkupdate.agent.plist
          [not loaded] net.culater.SIMBL.Agent.plist
User Launch Agents:
          [not loaded] com.adobe.AAM.Updater-1.0.plist
          [not loaded] com.facebook.videochat.elenicourea.plist
          [not loaded] com.spotify.webhelper.plist
          [not loaded] net.infinite-labs.SIMBLEnablerForSandboxedApps.plist
User Login Items:
          Flux
          GrowlHelperApp
          iTunesHelper
          Flux
          The Lion King Circle of Life.mp3
          Dropbox
3rd Party Preference Panes:
          Flash Player
          Flip4Mac WMV
          Perian
Internet Plug-ins:
          AdobeAAMDetect.plugin
          DirectorShockwave.plugin
          DivX Web Player.plugin
          Flash Player.plugin
          FlashPlayer-10.6.plugin
          Flip4Mac WMV Plugin.plugin
          googletalkbrowserplugin.plugin
          iPhotoPhotocast.plugin
          JavaAppletPlugin.plugin
          npgtpo3dautoplugin.plugin
          o1dbrowserplugin.plugin
          OVSHelper.plugin
          QuickTime Plugin.plugin
          SharePointBrowserPlugin.plugin
          Silverlight.plugin
User Internet Plug-ins:
          Picasa.plugin
Bad Fonts:
          None
Top Processes by CPU:
              44%          Google Chrome
              28%          WindowServer
              10%          EtreCheck
               7%          syslogd
               2%          hidd
               2%          Bluetooth File Exchange
               1%          fontd
               0%          Finder
               0%          SystemUIServer
               0%          JavaApplicationStub
Top Processes by Memory:
          210 MB             Google Chrome
          111 MB             JavaApplicationStub
          57 MB              Finder
          49 MB              Dock
          42 MB              Google Chrome Helper
          41 MB              SystemUIServer
          41 MB              WindowServer
          41 MB              Bluetooth File Exchange
          41 MB              quicklookd
          41 MB              EtreCheck
Virtual Memory Statistics
          382 MB             Free RAM
          1.01 GB            Active RAM
          518 MB             Inactive RAM
          2.10 GB            Wired RAM
          461 MB             Page-ins
          364 KB             Page-outs