will these work?
 

so my sister laptop is broken due to the worn out ac adapter.
the input are 100-240v 1.5A 50/60hz
output 19v=3.15A

and the ones that i found on ebay are
Input: AC 100V~240V 50~60Hz (Worldwide Voltage input)
Output: DC 19V 3.16A 60W (compatible with 40W)
Connector size: O.D 5.5mm *3.0mm with center pin

will these work for my sister Samsung laptop?

AC Adapter Charger (Power cord) for Samsung Laptop | eBay

I think it should work. The most important things for compatibility are the voltage and the connector type. Those two need to be exactly the same. The current from the adapter just needs to be >= 3.15A.

Moved to the computer forum.

There are a number of places i Richmond that sell A/C adapters for cheap. just google it.

unless they specifically mention your laptop model in the item description, i would try to buy one locally to ensure that the connector fits properly

most places will use Dr. Battery replacement.. it will be about the same..

ME and A-Power are good places..