XPS M1730 boot failure - LCD or nVidia problem ?

I have an XPS M1730 with the nVidia G92 9800M-GT2 / Physics Ageia video combination.  Until last month it worked fine.  Then I started experiencing boot failures - it would start up and display the Dell logo, but before the BIOS scan was completed, it would shut down.  Now, it shuts down every time.

Here is what it does:

Power light comes on
 HDD light active
 Cooling fan(s) come on
 Battery light is lit
 HDD sounds audible
 Start up screen with Dell logo appears
 BIOS scan indicator (horizontal bar) progresses to 75-80%
 Fan stops
 Power light goes out
 Unit shuts down
 Battery light remains lit

Dell Technical support says it is the LCD screen that is bad. !!  If so, why does the startup /logo screen appear?  According to Dell, because it doesn't display anything when booting with the "D" key (display test), it can't be the nVidia card, it has to be the LCD. 

I've also tried using an external monitor - but the PC apparently isn't capable of displaying anything to it.  The logo screen, as I understand it, is generated by the BIOS, and needs a FUNCTIONING display screen, but requires minimal power.

I don't buy it.  I believe it is the graphics card assembly.  Anyone else have a similar situation?