No power The dell c640 will not power up with the cord.  It will run off of the battery only but will not charge.  there is no lights for showing power only a yellow light when running on the battery.  Any suggestions?

chances are the actual power jack in the laptop has gone bad. this is a common issue with lots of laptops and every dell laptop (4) that i have owned http://www.ebay.com/itm/like/281152320878?ul_noapp=true&chn=ps&lpid=82

If the laptop battery is more than 3 - 4 years old then the battery could be worn out. Rechargeable batteries have a finite number of charge and discharge cycles and will lose their charge capacity over time, i.e. won't charge to 100% and gradually the charge reduces until the battery won't charge up at all. OR The battery shows a 100% charge but when the adapter is disconnected the battery drops off to zero capacity in a very short time. If the battery drops to an unacceptable charge level then the battery needs to be replaced. Rechargeable batteries will fail if stored in a discharged state for long periods.

try to change your charger.

You probably have a defective battery connection or circuit on the motherboard. It will have to be replaced or repaired.

The battery has a dry cell causing this so replace the battery

I suggest you DONT USE PINCH POWER CORD FOR SAFETY.

PLEASE TELL ME IS YOUR POWER CORD & THE PINCHED CORD ARE SAME? I MEAN SAME MODEL? AFTER PLUGING OF YOUR CORD, THE BATTERY CHARGING LIGHTS ITS ON? IF NO THEN I GUESS THAT CABLE NOT SUPPORT HER LAPTOP.
VISIT A DELL SERVICE CENTER OR A SHOWROOM AND BUY NEW CORD WHICH IS MADE FOR YOUR DAUGHTER LAPTOP MODEL.
OTHER WISE SOME CHANCES OF SHORTCIRCUIT ON MOTHERBOARD.

Thanks, i am waiting for your feed back & if you satisfied then thumps me please.

Occasionally a defective battery will show charge and not work at all. HP has the same problem on some models. Try a different battery and if it works, then the battery is defective.

If the laptop does not run plugged into AC power, then you may have a defective power brick or a power problem with the laptop.

I would try another power brick. If that doesnt do it then your power jack inside the machine may be damaged and usually that means the motherboard is cracked. The only fix in that case is a new motherboard ($150-$200 plus labor) OR you can get the Dell C PORT II port replicator which has its own power jack.

Hope this helps!

This sounds like it is not getting enough amperage from the power brick- check which model power brick you have. I'm not 100% sure but the pa-6 family may not provide enough power to charge and run the laptop at the same time. the PA-9 should- if it's rated at 4.51 @20v - that works out to about 90watt. If you DO have a 90 watt power adapter and it's still giving the orange then red flashes- and will not charge when the laptop is off- you probably have either a bad battery, or the motherboard is faulty and has a bad charge circuit, or a loose power jack. What does pressing the little button next to the charge indicator on the battery do? Flashing every other led- 1,3,5 is BAD, so is 1 and 5. You also might have a 3rd party refurb- that had the guts torn out and is not properly "seen" by the laptop.

I purchased a Genuine Dell Battery, It arrived dead with 1 test light on battery itself at 0% charged, It only lasted 2 mins before the laptop died running on battery, It doesn't charge the Dell battery at all The replacement battery only shows a 1% charge every 7 hours or so, nor do I have a yellow, green, orange light, The only time I get a light on the battery led is if i'm running on batteries and the battery level is below 10%, Its orange for low battery.
Thanks in advance to anyone who could help me.