Well I'm running it on a laptop. And it's not an overheating problem. I can run everything on ultra high basically in DS2 without any lag or problems what so ever. My laptop doesn't feel warm either and I can play any other game with no problem
Shut down itself is high likely caused by overheating from CPU or Power Supply. Since you are using Laptop, check the fan and ensure that it's running. Do not put laptop on your lap that covers fan prevent it to intake the air to keep it cool.
Personally, I hate gaming on laptop due to sensitive to overheating but yeah I know it's really nice to bring gaming to elsewhere but overheating can damage to computers.
If it's constantly shut down itself, I would recommend stop playing any games and send your laptop to a computer repair store and have them to check to prevent it from getting any further damage.
- Exor
[Edited by exoriax, 1/28/2011 1:37:01 PM]