Mavericks - Repeated crashes with strange screen artefacts on MBP late 2011

Question

After installing Mavericks on my MBP I experienced a multitude of problems. Most of them were resolved by uninstalling some incompatible software, repairing permissions, nvram reset. But I am stuck with a strange issue were the screen suddenly shows blue stripes, gray stripes or a distorted image of the desktop (freezes sometimes), see images.
Since this never happend before, the MBP didn't crash in a year, I thought Mavericks is to blame But no one else seems to have this problem, so I am afraid that it might be a hardware problem on my side (Hardware test didn't find anything either, though).
Does anyone have an idea whats going on here?

Answer 1

EtreCheck System Report:
Hardware Information:
          MacBook Pro (15-inch, Late 2011)
          MacBook Pro - model: MacBookPro8,2
          1 2.2 GHz Intel Core i7 CPU: 4 cores
          8 GB RAM
Video Information:
          Intel HD Graphics 3000 - VRAM: 512 MB
          AMD Radeon HD 6750M - VRAM: 512 MB
Audio Plug-ins:
          BluetoothAudioPlugIn: Version: 1.0
          AirPlay: Version: 1.9
          AppleAVBAudio: Version: 2.0.0
          iSightAudio: Version: 7.7.3
Startup Items:
          VirtualBox - Path: /Library/StartupItems/VirtualBox
System Software:
          OS X 10.9 (13A603) - Uptime: 0 days 0:50:42
Disk Information:
          TOSHIBA MK5065GSXF disk0 : (500.11 GB)
                    EFI (disk0s1) <not mounted>: 209.7 MB
                    Macintosh HD (disk0s2) /: 499.25 GB (176.53 GB free)
                    Recovery HD (disk0s3) <not mounted>: 650 MB
          MATSHITADVD-R   UJ-8A8
USB Information:
          Apple Computer, Inc. IR Receiver
          Apple Inc. FaceTime HD Camera (Built-in)
          Logitech USB Receiver
          Apple Inc. Apple Internal Keyboard / Trackpad
          Apple Inc. BRCM2070 Hub
                    Apple Inc. Bluetooth USB Host Controller
FireWire Information:
Thunderbolt Information:
          Apple Inc. thunderbolt_bus
Kernel Extensions:
          org.virtualbox.kext.VBoxDrv          (4.1.16)
          org.virtualbox.kext.VBoxUSB          (4.1.16)
Problem System Launch Daemons:
Problem System Launch Agents:
Launch Daemons:
          [loaded] com.adobe.fpsaud.plist
          [loaded] com.adobe.SwitchBoard.plist
          [loaded] com.bjango.istatmenusdaemon.plist
          [loaded] com.google.keystone.daemon.plist
          [loaded] com.microsoft.office.licensing.helper.plist
Launch Agents:
          [not loaded] com.adobe.AAM.Updater-1.0.plist
          [loaded] com.adobe.CS4ServiceManager.plist
          [loaded] com.adobe.CS5ServiceManager.plist
          [loaded] com.bjango.istatmenusagent.plist
          [loaded] com.google.keystone.agent.plist
User Launch Agents:
          [loaded] com.adobe.ARM.[...].plist
          [loaded] com.divx.agent.postinstall.plist
          [not loaded] org.virtualbox.vboxwebsrv.plist
User Login Items:
          iTunesHelper
          Dropbox
          Android File Transfer Agent
          Google Drive
3rd Party Preference Panes:
          DivX
          Flash Player
          Flip4Mac WMV
          Growl
          Java
Internet Plug-ins:
          AdobePDFViewer.plugin
          AdobePDFViewerNPAPI.plugin
          Default Browser.plugin
          DivXBrowserPlugin.plugin
          Flash Player.plugin
          FlashPlayer-10.6.plugin
          Flip4Mac WMV Plugin.plugin
          googletalkbrowserplugin.plugin
          JavaAppletPlugin.plugin
          npgtpo3dautoplugin.plugin
          o1dbrowserplugin.plugin
          OVSHelper.plugin
          QuickTime Plugin.plugin
          SharePointBrowserPlugin.plugin
          Silverlight.plugin
          Unity Web Player.plugin
User Internet Plug-ins:
Bad Fonts:
          None
Time Machine:
          Time Machine not configured!
Top Processes by CPU:
              18%          mds
              13%          firefox
              10%          Dropbox
               3%          WindowServer
               1%          EtreCheck
               1%          SystemUIServer
               0%          sysmond
               0%          Dock
               0%          fontd
               0%          Google Drive
Top Processes by Memory:
          664 MB   firefox
          639 MB   Finder
          401 MB   Adobe Photoshop CS4
          188 MB   mds_stores
          180 MB   Dropbox
          180 MB   com.apple.IconServicesAgent
          106 MB   Google Drive
          98 MB    WindowServer
          82 MB    SystemUIServer
          82 MB    Preview
Virtual Memory Statistics:
          2.20 GB  Free RAM
          3.54 GB  Active RAM
          1018 MB  Inactive RAM
          1.25 GB  Wired RAM
          462 MB   Page-ins
          0 B      Page-outs
Tried the Hardware test before, which didn't show any issues.