Studio 1558 - No POST, Will not boot

3-4 months ago I experienced this same problem with my Studio 1558 (see: http://en.community.dell.com/support-forums/laptop/f/3518/t/19529101.aspx) -- black screen on boot, no POST or ability to even get to the BIOS setup.  I've diagnosed it the same way, by reseating the RAM, checking the HDD cable and doing the LCD test (which did produce colors on the display).  The laptop was (and still is) under warranty, so Dell replaced the system board, which fixed the problem.

After doing the system board replacement, the technician mentioned he thought the laptop felt like it was running a bit hot, and confirmed this by running some sort of diagnostic utility that reported the temperature (not sure if it was just CPU or also GPU and HDD temperatures).  At that time he didn't seem overly concerned, but suggested that if I ever had additional warranty work done, that I request the fan be replaced as well as he thought it wasn't working as efficiently as it should.

I think this may have been the root cause of my previous problems, and has resulted in a failure of the replaced system board as well.  For several days before this latest problem, the laptop shut off suddenly and would not boot.  After a half-hour to an hour of resting, it started normally.  This happened half a dozen times perhaps over the course of several days, and the machine will not boot at all now.  This sounds, to me at least, like a heat related issue.

I guess what I'm wondering is what is the best way to initiate some additional warranty work?  Is that something one of the helpful Dell reps here can do?  Is there some additional troubleshooting required first, or additional information needed from me?

Thanks!

- Darryl