Laptop power - really annoying problem, help appreciated!

Dell Inspiron 1501

Hey, I'd really appreciate some help with this.

I took my laptop apart in order to get rid of all the dust inside it. I then put it back together. (I'd never taken a computer or laptop apart before.) At the end I was left over with three or four small screws.

The laptop then would not work if the battery was inserted (with the AC plugged/unplugged.) The only way I could get the laptop to turn on was if the battery was not inserted.

Here's an example of an occurrence that was happening:
1> With the battery out and the AC in, I turned on the laptop.
2> Then I inserted the battery.
3> The laptop cut out.
4> I then removed the battery. And then the only way I could get the laptop to turn back on again was to unplug the socket from the wall and plug it back in.

I talked to Dell support on the phone. They said it sounds like the battery was damaged. Thankfully, my battery was still under warranty, so I returned it and they sent me out a replacement. (not Dell. I had bought the battery from a "Trusted Seller" on eBay.)

However, while this new battery works, the laptop will now only recognise either the battery OR the AC. It won't recognise both at the same time. And this means it won't charge the battery. The battery ran out of power. And when I have the laptop running on AC, and insert the battery, the laptop cuts out just as before.

The battery appears to be still functional, but merely out of power. (I did the green-light check on the battery.)

Anybody any idea what I need to do next?

Thanks!

Cheers for all the info, guys.

I'm gonna take it all on board, proceed, and then report back.

Hey, so I finally got round to taking the laptop apart again today. I took photos of the individual parts. I don't know what other parts photos I should upload...? I've chosen just the screws and both sides of the motherboard...

I need to reassemble the laptop so that it works as it originally did. Any advice?

Screws: http://tinypic.com/r/4hxzjo/7

Motherboard: http://tinypic.com/r/33wtqnl/7

Motherboard: http://tinypic.com/r/f5u08/7

Thanks, dave-P!

I put it back together, instruction by instruction as per the Dell assembly guide on their website. I had every screw required. (Except for one of the two for securing the keyboard)

I put the brand new battery into the laptop. I connected the power cord to the laptop and then plugged it into the wall socket.

I turned on the laptop. It came on. The battery light came on green and the computer started to boot. The Windows logo came on the screen. The battery light turned to red. From this point onwards, the battery refused to charge.

I shut down the laptop. I disconnected the battery and the power cord. I reconnected the power cord and turned it on. It came on. It booted up. While it was on, I inserted the battery. This caused the laptop to instantly cut off.

In short, it seems that the battery and the power adapter are point blanc refusing to cohabit. The laptop is telling them it has to be one or the other, but not both

And since the battery and the power cord can't function together, the battery can not charge.