Owning an M1330 myself, I know that problem well..
Your graphics card is stuffed.. Well melted actually. The M1330 has always had a problem with cooling the graphics card and processor effectively. Mine has had this happen twice so far, with the symptoms being a shut down and restart, with vertical lines forming all over the screen.
I would ring Dell, since this was a design fault with the laptop, you may be able to get the problem fixed at their cost. If they won't you're looking at a Motherboard replacement, which will be fairly pricey.
After the last time I followed these instructions to "Copper Mod" the graphics card to help the cooling. It does void your warranty, but does allow the system to run cooler.
Copper Mod
The M1330 was a great looking laptop with some great specs when it came out. But was so poorly designed it has put me off Dell laptops.