Dell 3800 will not start up

[mrlimpet]

I have a Dell 3800 and the symptoms are; my son was using the laptop and it shut down in the middle of internet use. When I pressed the power button the light on the unit will light up, you can hear the optical drive start up and with in 10 seconds or less it shuts down. There is no display no beeps or anything.
Things i have tried;
Removed battery and started up on ac only (same results)
Removed optical drive (same results)
Hooked up an external monitor(same results)
I went out to read different forums and everybody pointed to the motherboard. I ordered a new motherboard and installed but with the same symptoms of shutting down. I thought maybe it could of been the processor, ordered a new processor and installed and received the same symptoms. I know I have spent more that what the laptop is worth, but now it has become my mission to get this thing working. Does anybody have any ideas which direction I should turn next? My neighbor and I could not find the reserve battery on the mother board and i found out from Dell it is located under the palmrest, could this cause the problem? If it turns out to be a $10.00 battery i think I will just go crazy!! Please help while I am still sane.
Thanks
Mrlimpet

 

[michael555]

does this only happend on the net?

Sound like it,s fail the boot up test

Don,t think it,s the battery because you can use a power pack with a laptop

 

[Ian]

The backup battery is just to retain date/time information, so I don't think replacing that would help - it sounds like it's a problem with the power supply/power board, as you've managed to rule out the motherboard.

 

[mrlimpet]

I forgot to mention that I have switch the power supply with a different one and received the same results. The only things that I have not replace on this laptop is the Hard Drive and cmos battery. I have tried to power up without the hard drive thinking I would get an error on the screen but again the screen does not fire up and I receive no beeps. I am just about ready to give up. Thank for both the replies I really appreciate them.