send it back to dell and have them fix it for free or give you a refund... that is an expensive computer and they should be stepping up to the plate to make sure it works.. 100% without issue, delay, excuses etc, they should honor the waranty and actually fix it...

At the least they should re-solder/replace the bios chip and backup battery, if that doesn't fix it, or if they only do FRU type replacmeent, they should be able to replace the main board, including the graphics chip and CMOS/BIOS..