Just noticed there is a Bucheck 0x116 TDR error with atikmpag.sys (4/13/2012) i.e. your display drivers.
- Remove the Display drivers from Device Manager and uninstall application.
- Download Phyxion.net - Driver Sweeper and do a Driver Cleanup for ATI.
- Reboot the system
- Download Driver from Dell's website
- Right click on the Setup and go to Properties and under compatibilty tab change it to Windows 7
- Install the drivers
- Then download Windows 8 RP drivers AMD Catalyst and install it
- Reboot it again and see if that makes any difference.