I have a dell inspiron 9400 laptop. The computer has 2gigs of ram, an intel core 2duo processor(2.33), and a Nvidia Gforce 7800(seperate from motherboard) in it.

A few months ago, the screen went completly white, and overheated. I turned it back on like 12 hours later, and it worked just fine. Or so I thought it did at least, I was listening to it, and the graphics card fan, and the cpu fan were both not turning on. I tested the fans in it, and they work fine, so the problem is not the fan itself. I also tried buying a motherboard off ebay, and that still didnt fix the problem. If you have any ideas on how to fix this, please tell me.

Got a voltmeter? Check the voltages at the fan plugs

Nah, I dont have one. I just put a new motherboard in it though, and a brand new fan.

I tried one other thing though.
I unplugged the hardrive, and turned it on... still didnt come on
I took the graphics card out, the fans still didnt come on.
I unplugged the processor.. lol, the computer didnt stay on for longer than 3 seconds, the fans didnt try to come on though


If I unplug everything at once, and just make it a motherboad with only the fans connected, will the fans come on?

Edit: The fact that this is a laptop didn't register. Doh...

LoL, wait, this isnt a desktop PC, this is a dell laptop. And I tried to remove the Processor, not the PSU. The PSU is built into the motherboard I guess.

Anyways, thanks for the response though, I dont think I can bypass this that way on a laptop.

I don't see how unplugging anything is going to make the fans work. That doesn't make any sense. The only way to know if power is reaching the fans is to check the solder traces on the system board with a voltmeter.
Buying a motherboard off eBay is a crapshoot. I've had success, but you never know.
How do you overheat a LCD screen?

I just figured there could be another problems besides the motherboard thats stopping the fans from working. I mean, I already know the fans work, I bought a brand new one from a store just to test it, as well as an additional fan off of ebay. I already know I'm not getting any voltage from the motherboard. I mean unless the guy gave me a motherboard with the exact same problem as mine, couldnt there be something else stopping the fan from turning on?

Would it be worth it to take the motherboard somewhere... and have them test it, even though I could buy another new one for almost the same price?

If you don't have the tools or the ability, yes. Go to the small "mom and pop" computer repair. Best Buy will just want to sell you a computer

Come on... your thinking too simple here. Ive been looking around, and there appears to be lots of other problems that can go wrong to make laptop fans not turn on. I just need to find someone who has had a similar problem to mine. I know the laptop is reading 0 volts already.. why would I test this.

Oh.

You dont, the computer overheated, which inturn caused my computer to crash, and I couldnt do anything at all on it. Then the screen went white.

Assuming it is apart and cold when doing so, I would think that would be normal.
Might want to take a look in the bios cooling fan\temp settings if you haven't already.
Went over to the dell forums and there is a couple threads on the e1700, the 9400's american sister, in which the issue was corrected with a bios update. Even though it does not specificly address that issue, the latest bios version download with instructions are here if you wish to give it a try.

Alright, Ill try that, and tell you how it went when I get done. Thanks.

Yea, It still didnt work. I'm took it to a laptop shop... and I guess they will tell me whats wrong with it ^^. Thanks for the help guys