Computer shuts down before POST

I am so stumped. My moms friend gave me her Dell Inspiron 5150 laptop to fix. Reason to fix it was that it kept shutting off after about 5-10 seconds before the post. When I unplug the hard drive, cd rom, floppy, network card, it still did the same thing. I unplugged the processor and it stayed on. So thinking it was the processor. I got a new one for like $50 bucks. Plug it in same problem. This also came with a new fan as well. So i know its not the fan or processor or hard drive, or cd rom, or network, or any additional components. Now the only thing I can think of is two things.

1.) I never get video on when I boot. Nothing is being displayed on the laptop screen, I even plugged in a regular monitor and still no image. Would video make it not boot. I'm thinking no cause it will stay on when the processor is out. ?????????????????
2.) Is there anyway I can wipe the BIOS and start new. I know I can with my desktop. I just move the jumper setting. But on this laptop I dont see anything for that. ??????????????

Help please.

Drew

P.S. I have also tried 2 different power supplies.

Did you take out the HD and pheripherals out the laptop?! How did you manage to take out the processor?

I have everything out. The only thing in is the motherboard, the chip (P4 2.4) and the heatsink fan over top of it. And it only works when I have the chip unplugged. When the chip is in it shuts down. I have tried 3 different chips. The chip is the processor right?

Curious. You say that the computer shuts off after 5-10 seconds but you've never been able to get the video working. I assume therefore that the only indication that the computer works at all is that the PSU fan turns. Do you get any other indicators from the laptop? Lights? Hard-drive noises? CPU fan? If not then what's probably happening is that the PSU starts up, looks for a response from the motherboard, doesn't get one, decides it's not needed right now and goes back to sleep. Admittedly I've only ever seen an AT PSU do this, the type where the power switch is connected directly to the PSU, not via the motherboard, though your system may have similiar functionality. In my case the problem was a loose RAM chip, once the RAM was inserted correctly the computer worked fine. It's a long shot but check if the RAM is inserted correctly and it if is try replacing it with known working RAM (but please don't buy some specially for this, I'm taking a wild guess here so I'm probably off the mark). Otherwise tell me everything that the computer actually does when it's turned on, noises, beeps, lights (including keyboard), and I'll see if I have any other ideas.

Ok Im not sure what fan is the PSU one and what one is the CPU because there is only one fan which is connected to the heat sink. The power lights turn on when I start it along with the keyboard lights (caps, numlocks, etc.). I tried the memory thing but no luck. The only thing I can think of is video??????? But it should just beep at me though right?

base836ball said:

Ok Im not sure what fan is the PSU one and what one is the CPU

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The PSU fan is normally the one that goes inside the power supply though laptops probably don't have one come to think of it.

base836ball said:

The power lights turn on when I start it along with the keyboard lights (caps, numlocks, etc.).

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OK, so there is some power getting through the motherboard.

base836ball said:

I tried the memory thing but no luck. The only thing I can think of is video??????? But it should just beep at me though right?

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Not necessarily, BIOS beeps can be useful but are not totally reliable as there are certain basic factors that need to be present in the computer before the speaker will work at all. My next best guess is that the processor is overheating which the BIOS detects and shuts the computer down to avoid frying the CPU but that should have been taken care of when you changed the CPU and the fan. Perhaps the problem is with the BIOS itself. If it can be removed physically from the motherboard then do so and make sure the socket for it is dust-free and that you re-insert it correctly. Sounds wierd but I do remember a fairly recent thread on this forum (can't find it unfortunately) where one guy had a similiar sort of problem with his computer (not a laptop). After several questions back and forth he fixed the problem by removing the BIOS chip and replacing it so it's worth a try. If it's not that then the video idea is worth a look for the simple reason that you seem to have tried everything else!

Yea my main idea was to clear the BIOS but I cant find it. There are no jumpers and the CMOS battery is connected to 2 little clips that will break it off. Unfortunately the video is built into the board. Looks like I am SOL on this one. I will just go buy a new motherboard unless someone can tell me how to clear the BIOS.

Thanks for all the help ThePenguinCometh

base836ball said:

Thanks for all the help ThePenguinCometh

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You're welcome.

I've fixed/revived/messed around with a lot of computers in my time but laptops I generally leave alone. Everything is usually hard-wired in (on the theory that laptop users are less likely to upgrade their machines then desktop users) so they can be a bugger to fix. If your feeling brave/desperate then you could try breaking the BIOS out and soldering it back in again! Pretty extreme I know but theoretically possible and I've seen similiar tricks working, though being a laptop you'll probably need to be very accurate with the soldering iron.