* Go here* Install the latest BIOS, Intel Chipset, Alienware Command Center Application, Alienware OC Controls Application* Restart the Laptop after each one is installed* Run the pre-Windows ePSA Diagnostics- Turn the Laptop off- Connect the external power adapter to the Laptop- Turn the Laptop on and press F12- Highlight Diagnostics and press Enter- Click No when prompted for the extended memory test
I have a 5155 inspiron where the bottom gets really warm. The location is the center back.  The processor thermals seem okay.  The max I have seen is 93c under load, but for the most part stays under 55 when just surfing or doing basic tasks (though it spikes higher when charging).  So it isn't like the laptop is overheating, it is just uncomfortable to put on my lap for any length of time.  I had another of these that got exchanged due to screen issues and it didn't have this issue.  I am trying to find a solution, but haven't found one yet.  Hoping for suggestions.  
Dell 5155 bottom gets hot