Dell has identified three possible root causes to this lockup symptom - 1. BIOS CPU power management 2. Loose AMD Radeon HD6950/6870/6770 video card 3. Possibly defective main memory modules
BIOS CPU power management * Turn on (or restart) your computer * When the DELL logo is displayed, watch for the F2 prompt to appear and then press F2 immediately * Go to Advanced- CPU Configuration * Disable CPU C6 Report * Press F10 and exit the Bios saving your change * Once into windows, restart the PC one more time * Test the XPS 8300 for lockups
Loose GPU * If lockups still occur, power the XPS 8300 off. Disconnect the XPS 8300 power cord from the rear of the tower. Open the case cover. Does your AMD Radeon HD6950/6870/6770 video card have a black bracket affixing the rear of the video card to the chassis via two screws? If not and your in the Americas, I will need to ship the Graphics Card Holding Bracket part number V32TR out to you. Once you receive the bracket, you simply power down, open the case cover and affix the bracket to the end of the video card and the chassis using the two screws. If your outside of the Americas, contact Dell Support for your region.
Defective RAM * Download and run CPU-Z. Click the SPD tab to identify your memory. The next item to check is your memory. If you have GR82X 1GB, G8NT0 2GB, or 9V62Y 4GB memory sticks, remove them from the system and retest for lockups with just the other memory sticks installed. So if you had that memory in the white slots, remove it and move the other memory into the white slots. If the lockups cease when the memory sticks are removed from the PC and you are in the Americas, I will need to replace the defective memory with a different vendor memory of the same size. If your outside of the Americas, contact Dell Support for your region.