Dell Inspiron 1000

Try another AC adapter - Those use a simlar charger to a lot of toshiba and compaq notebooks - something in the 18.5-19v and 3-4a range will work or a universal targus/kensington kit.

If a different adapter does't do it then you may have a power jack that has broken on the inside of the laptop. Normally about $100-$150 repair - get a recommendation from someone for a local repair shop that has had a laptop repaired (ideally for this same problem) There is a wide variation in the quality of techs that work on laptops.