Dell 9400 wont show AC power icon

As long as you buy a genuine Dell AC adapter, it will be find.
Do not buy a 3rd party AC adapter.

I have bought at least a dozen Dell AC adapters on eBay. Just make sure the photo shows a genuine Dell.
http://www.ebay.co.uk/itm/Original-OEM-Dell-Inspiron-Mini-10v-Battery-Charger-Power-Supply-Cord-19V-30W-/190678344193

try to charge the battery while the computer is off for 3 hours. if that does not work, remove the battery from the computer and turn on the computer using only the ac adapter. if the computer is working fine using only the ac adapter, call your computer manufacturer for possible battery replacement

This sounds like a problem with the AC charger not providing enough power. The battery never charges enough to maintain power during boot. See if you can borrow a charger to check (maybe from a local shop), or buy one (since you'll probably need one anyway). Don't over pay. I see them on eBay for $12 or so. I bought one recently from a local shop for $25. That should give you a ballpark price. Post your zip code, maybe someone here can help you.

Troubleshooting is pretty simple.

1. Try a different Dell 90W or larger D/E-Series AC adapter and see if the system gets power. If no known good AC adapter is available, then check output voltage of AC adapter (Should be about 19VDC or so) If you can't do either, then the AC adapter is still the cheapest item to replace for a no power issue.
2. If system will not power on with a known good AC adapter or new one, then the motherboard is the likely failure point. Roughly $150 on Ebay

It shows no power on your laptop but it shows you the dvd player led comes on then off. I would suggest try the following:
1. Remove laptop battery, optical drive, hard drive and ram. Remove external peripherals as well. 2. Make sure AC Adapter is not yet connected to the laptop. Press and hold on the laptop's power button for 10 seconds to drain the power flea. 3. Connect the AC Adapter to a known good power outlet, check AC Adapter power LED if it is on. Try to sense if AC Adapter is not making a bit of noise when it is plugin to the wall power outlet. 4. Connect now the AC Adapter to the laptop. Check if AC Adapter LED stays on when it is connected to the laptop. If the LED stays on means the AC Adapter is fine. If the AC Adapter LED turned off check the AC Adapter pin that goes to the laptop AC socket if it is loose. 5. If AC Adapter stays on after connecting to the laptop try to power on laptop. If no power LED comes on then this is motherboard problem. 6. Before replacing the motherboard there is one checking needs to do. If you can open your laptop bottom part then good, do this when laptop is not connected to any power source. Try to reseat the laptop CMOS battery then try to power on laptop after, if still fails then replace motherboard. I hope this helps.

Only A Couple Things You Can Try Here.....

You Can Attempt To Clear the BIOS By Removing The CMOS Battery...
You will have to disassemble to get to it...Not sure offhand on your exact model whether your battery is plugged into the motherboard or directly soldered.. I am almost certain yours is a Snap in/out that gets inserted into a carriage on your motherboard... Either Way... You Will Need to remove it... Make sure your Power Battery is also removed... and your AC Adapter is not plugged in..
Then Press and Hold Your Power On Button To SHort Out The Connection... THen After 30 seconds or so.... Reinsert CMOS Battery...
Reinsert Power Battery...Plug In AC Adapter...
Attempt To Power On


Didn't Work... Option 2:

Try Using A Backdoor Password Or Default Pass...Go To THe Following Link For More Info On It: http://www.tech-faq.com/reset-bios-password.shtml

Still Didn't Work... Option 3:

The BIOS Will Either Need To Be Flashed... Or You Will Need To Replace The Motherboard...

The BIOS ROM CHIP can be flashed (erased and written over) but it is costly... you Can Google Search That Information If You Choose To...
Use Search Term: Dell Inspiron Bios Flash

(before you do anything remove the battery and th ac plug)remove the memory inside small door on the backside that has a "M" on it now once you remove the memory install the battery, power on if you hear a couple of beep tones you are half way there the motherboard is good so the problem is what you took out so there are two memory slot try them in the A slot one at a time.If the problem is memory replace it.
Good luck

Does the laptop power up just no charge the battery? If the laptop does not power on then you may have a bad power supply in the unit. If it does power up than you most likely have a bad battery connector of blown fuse on the motherboard. The flashing of the BIOS is done with a bootable cd or floppy but this will not keep the new battery from charging. The reason Dell states that you need at least 10% battery to flash a BIOS is because if your AC power goes out while you are doing a BIOS upgrade and you don't have battery power the BIOS will be incomplete and your laptop will not boot again without replacing the motherboard.

Try taking out battery and plug in power. If it works, battery is faulty. If not,
Try taking out your hard disk plug in power, if it works, hard disk is faulty. If not,
Try taking out memory card, if there's a sound, memory card faulty. If no sound, it's your motherboard that is causing the error.

Note: If machine is under warranty no need to pay for the repairs.

I have a Dell Inspiron 6000, and so does my wife. One day coming back from the airport, the power adapter cord(the end that plugs into the laptop) was hanging out the door and was dragging on the ground. Well the end was unusable and I was out looking for another AC adapter. Dell wanted $80 for a new one, but I found one on ebay for $40. But once I got it, I found that it would power my laptop, but wouldn't charge my battery. I thought, I know the old one works, so I cut the end off the ebay one and wired it onto the original one but ended up with the same result. Called the ebay seller and turns out these AC adapters are dell seconds. They claimed to test them and offered to send me another one and did so. By that time the new one from dell dropped to about $40 so I just bought it too anyways. The new dell one worked and the second one from the ebay seller did the same as the first one he sent me. I found out that the dell laptop wont charge the battery if the supply goes below 19.5V. By me hacking the other end on the original AC adapter, didn't result in the best insulated connection from the other wires. Also, if anyone know anything about AC adapters, is that they have a "Step Down Transformer," and the company that makes them, low balls the windings so that if they are off on the voltage, they are under, and not over, thus not frying the more expensive laptop. My suggestion to you is to just pick up a new AC adapter from dell. Also, the rubber coating on the cord is pretty soft and splits easily.