Running a laptop repair service in New York, and having all laptop brands for repair day by day helped me to categorize most common laptop problems brand by brand. I will talk today about Dell laptops. For DELL laptops the most common problems that we face are power problems, especially power jack problems. The symptoms are: the laptop is running on battery only, has no power, or will not charge the battery. We recommend a full jack replacement, not just solder the pins of the power jack on the motherboard as they will fail again as they did it first time. A new power jack will last more and the part it is cheap if bought from E-bay. A power jack replacement will save you from changing the motherboard, and the cost is almost half than the motherboard replacement. The only problem is that Dell laptops, after a power jack replacement or a motherboard replacement have the tendency to not recognize the AC-DC adapter or the battery.
This is happening mostly at Dell laptop, but we found a fix that worked in most of the cases. After you changed the Dell power jack or replaced the Dell motherboard, before starting the laptop remove the CMOS battery for 5 minutes for BIOS reset. You will need a dell compatible AC-DC charger and a dell compatible battery charged above 10%. Start the laptop and press F2 key. It will take you to the BIOS setup. In setup fix the clock. Restart saving the changes. When the new BIOS message appear press F1 key to continue. When in Windows go on the DELL website, search for your model drivers, according to your model and download the BIOS upgrade. Run DELL BIOS upgrade, and the computer will restart and upgrade the BIOS. When started again, your laptop will hopefully recognize the battery and AC-DC adapter.
If the Dell laptop will not recognize the battery or the charger after those steps, then your parts are faulty.
You can easily check the battery by pressing the battery state button located on the back of the battery. If the battery is good it will light green showing the amount of charge. If nothing appears, that means that your battery had its days and need to be replaced.
The AC adapter can be checked with a voltmeter, or if the laptop it is running on battery but not on AC adapter try another one if you have one.
Good luck and hope all these will help.