If you have not yet tried a new Dell AC adapter, that's next.  If it doesn't solve the problem, the mainboard will need to be replaced.

BIOS update, found at ftp://ftp.us.dell.com/bios/1525_A17.EXE   It is an issue with some intel northbridges used in laptops, so is common along several manufacturers, I had an HP with this very issue.

I haven't seen any statistical evidence that Dells are more prone to power failures than others - in fact, the HP you speak highly of is the one that has a much worse reliability record:
http://www.lockergnome.com/blade/2009/11/17/notebook-reliability-asus-the-best-and-hp-the-worse-what-do-you-think/

The mainboard?  I believe my adapter is working fine.  When I plug it in to my laptop it works fine.  You would think Dell would recall the inspiron 1525 and other laptops, being that this is a common issue.  If the mainboard needs to be replaced then I would think that would be quite expensive.  Better off to go buy a new one.  Probably will not be buying a Dell though.  I've had a HP laptop for almost 5 years now and had no issues.

The BIOS update won't work unless your battery is at least 10% charge; mine is zero. Can't charge because the BIOS needs to be upgraded and I can't apply the BIOS because the battery is 0% charge.

I purchased 2 of the 1525 laptops at the same time in November 2008; one for a friend. Oddly enough, they have different versions of the AC adapter.  The other one works fine on my laptop and charged the battery so I could apply the new BIOS.  After applying it did a reboot and when I logged in and checked the icon, it still said "plugged in, not charging".  I said 'Oh well, so much for that' and let it sit while I watched TV.  I came back later and it said 100% charged. I let it run on just the battery for a while, then plugged the adapter in again.  "Battery level 97%, charging".  So it seems to be charging again. We'll see how long it lasts.

is it still working? I just put that bios in and its still saying the same thing..

After we did the BIOS upgrade the charger worked steady for about a couple of weeks. Now it works intermittently.  My son gets mad when the battery goes to zero because he has to shut down if he wants to move anywhere.  Other times the battery will charge for days at a time.

His friend has an identical laptop; we purchased them together.  I can put my son's battery in the other laptop and it will charge. If I put my son's AC adapter on the other laptop it won't charge at all.  If I put the other laptop battery in my son's with the other charger, it works.  I don't see how it can be the mother board but that's what everyone says. I think it's a combination of things because Dell buys parts from many different suppliers.  I'd replace the AC adapter but others that have done this say it helps for only a few weeks then the problem returns. 

I won't replace the mother board because it's too costly and too much work.  Because of all these problems I won't replace this 1525 with another Dell.  I'll be looking at HP for my next one and turn this one into a desktop until something else fails.

It sounds more like you have a faulty AC adapter - though it could be the power jack ( which is on a $100 power board, not the mainboard).

Beware before buying HP-  their hardware is the least reliable out there and their support is bottom of the barrel.

>It sounds more like you have a faulty AC adapter

If the AC adapter were faulty, how could it provide enough power to run the laptop? It has a stated DC output which seems to be running the laptop just fine even though it's 'plugged in, not charging'.  It does this on the other 1525 too but posts in this forum state that replacing the adapter didn't solve the problem for very long, same as the BIOS upgrade.:emotion-40:

> though it could be the power jack

If the power jack was bad, why would the problem follow the adapter when I move it to another 1525 that doesn't experience the problem with its own AC adapter?

Yes, I thought of these and I'm happy to have another properly functioning 1525 to test with.  I think it's the mother board and I'm not spending the money to replace it.  I own 4 Dells and the Dimension XPS Pro 200n is still chugging along. It stayed plugged in and running from 1997 to about 2004 when I bought the Dimension 4700 which I have to run with the side panel off to keep it from shutting down with an 'overheating' error, also fixed by replacing the motherboard.  The Inspiron 531 so far is running OK.  The 1525 laptop has its power error.  I thing it's time to move on, maybe not with HP but with another supplier.  I'll have to do some research.

You'd think Dell would research this issue and provide a final fix for the problem.  People in this forum reported they've tried the BIOS upgrade, replaced the mother board and replaced the adapter only to have the problem return within a month or less.  For that kind of money I can buy another laptop.

Thanks for your suggestions, though.  I appreciate the replies.:emotion-2:

-Rich