When I was putting my charger into my backpack, it was fine, but when I tried using it at my cousin's house it didn't want to charge my laptop. When i put my ear next to the transformer, I heard ti ti ti ti ti ti. I knew something was wrong. Any guesses?
Do test your AC adapter if it's supplying enough voltage to your laptop first. Remove the battery off the laptop then power the laptop with just the AC adapter connected and see if it will power the laptop. If the laptop will still not boot up with just the AC adapter connected that means the problem is the charger. The last test you can try is to use a different AC adapter that has the same voltage and see if it will power the laptop or not, and if a different charger will work that means the only solution would be to replace the AC adapter.