You mentioned you tried 3 different chargers for your laptop with the same battery right, did you get the same result with all those 3 chargers? If yes, that means it's a clear battery problem but here's a link from Toshiba that will help you how to run a check with your battery using a Toshiba software.
Try googling the battery power pins layout (to see where is power in/out) and make a "extender cable" to charge it without charging circuit. (safety first ) Take measurements of the charge (amps and volts) leave it to charge for 10 minutes and take new measurements. If there is no change the battery is most likely dead if it actually charged it its probably the circuit failing. Or go as Laptop_Nerd said. Its better than my way