I was thinking it looked expesnive but it's a laptop, so not a bad price ^^

I wouldn't really know what the problem is, but it could be the bad nVidia thing. You could try turning settings down while playing to reduce heat, though I would return it as faulty goods (especially now it's knackared).

Never had a Dell, so I can't help you there, I'm afraid.

Business support here has always been good with Dell but that was because we shelled out an absolute bomb on their extended premium business support packages... I have heard bad things about their home support.