STOP. Don't do it.
You cannot use a 19v supply where 16v are expected, even if the connectors happen to be the same.
Here are some of the bigger reasons:
1) The polarity could be different between the supplies. If it is: zap, lappy deceased.
2) The 19V supply will cause the internal regulators to have to dump extra voltage, which is given off as heat. It will likely overhead the regulators soon and ultimately damage the laptop.
3) The current rating on the 19V supply is lower because it provides extra voltage. Unfortunately, that extra voltage is wasted on a 16v laptop so the power supply wouldn't have enough power to keep the laptop running.
In short: buy a new supply made specifically for that laptop.
Raydude