That's a classic hardware issue. If it's fine when cold and not after a few hours on the next boot, you are back to Dell to get it fixed.
Then again I'm still finding folk that will not accept you can't use this on a couch or bed! Those folk will be great for the industry as they burn through the gear.
I have an Alienware M17X R2. To sum up, I had the screen and one video card replaced (one of my two HD Radeon 4870). Since then I have had problems.
Windows 7 can be installed but after a few hours I get blue screens of death at startup. Ubuntu 12.04 cannot really be installed. At the end of the day the only operating system that will run is Ubuntu 12.10.
I believe I have understood why the only operating system that would run on my laptop is Ubuntu 12.10. It is the only operating system I have tried that does not install the proprietary drivers for the video cards. Even then, if I try to install those drivers on Ubuntu 12.10 in order to use my HDMI connections I end up with permanent black screen. As long as those drivers are not installed Ubuntu 12.10 runs just fine.
I would like to add, for what it's worth, that when I install Windows 7 (before getting BSODs) the device manager does not detect any problem with my video cards.
Does it sound like a hardware issue or a software issue ? Any idea what could lead to this mess ? Any fix ?
Sorry for this quite long post ... I try to be as precise as I can.
Any help is greatly appreciated