I recently picked up a non-starting Inspiron 600m. The symptoms:
Push the start button, three lights come on (numlock, etc) for about 4 seconds, then off. The end.
The fan never spins, nothing happens on screen.
I've swapped power supplies, gradually stripped the machine down, removing battery, CD drive, hard drive, wifi card, RAM, pulled the keyboard, disconnected the screen. The symptoms haven't changed.
It looks new inside - no lint, hairballs, etc.
I'm pretty sure it's a motherboard problem, but thought I would check here before spending $200+ for an eBay mobo.
Have I overlooked something?

hmm, how and from where did u pick it up?? didnt the original owner tell u whats wrong with it??? i wouldnt of bought it if i didnt know the exact problem.... maybe it IS the motherboard.

The original owner knew it didn't start, and didn't want to pay for having it fixed. She gave it to me as payment for fixing another computer.

did she at least tell u whatsup???

Actually, I was just hoping that someone on this board would read this laptop's symptoms and suggest some way to fix it short of replacing the motherboard.

im sorry but, with the information you gave us (which is non) we cant really read the symptoms, try your luck with a new motherboard, if its not it, then re-sell it on ebay, and sell the whole laptop as parts. cheers.

I had these same syptoms with my i6000d when the processor was toast. It would light up for a few seconds then just turn off. I'd try picking up a cheap processor and trying that out, thats your only option at least short of the motherboard. I have a pentium m 730 (1.6ghz, 533 fsb) that dell replaced my blown processor with id sell you cheap.

edit: i just checked, the 855 chipset wont support a 533 fsb. good luck.

Thanks for your response ocspecv, a known-good processor would sure make the diagnosis easier.

no thanks for me! lol im sorry stmojo im always very negative.

Well, I found a processor to swap in as a test - no joy. Found a used mobo on ebay, the 600m now starts and runs, all is good. Well, almost. At startup I get the message that the adapter type cannot be determined. So it runs fine plugged into AC, but the battery won't charge
Apparently this is a not-uncommon problem with Dell chargers. The adapter is a PA-12, the critical center pin is intact. The 19.5 volt output is OK, the center pin looks like about 2 millivolts. I don't know it that's what it should be, can't find the specs for it. I suspect the power supply is not the problem.
Anyway, I have a working 600m, but may have swapped a bad motherboard for a flawed motherboard.

contact the guy who sold u the motherboard and tell him u want an exchange or you hunt him down where ever he is and shove his mobo up his face.

Thanks, Levon. Helpful advice, as always.
You have a working adapter for your red 600m, right?
Could you check the output of the center pin on your adapter, to verify if mine is working correctly?

how could i check that????????

Levon, if you have a multimeter set to read DC voltage, touch the black (ground) lead from the meter to the outside of the barrel of the power supply plug. Touch the red lead from the meter to the inside of the barrel - the meter should read around 19.5 volts. Touch the red lead to the little pin down inside the barrel, see what the meter reads. The easiest way to touch only the center pin and not the inside of the barrel is to cut a bit of a small plastic straw that will drop down inside the barrel.