A/C adapter power cord swap

The A/C adapter on my Gateway just died. I have an HP lappy adapter that I have as a spare. My question is: can I use it? Here are the specs for the Gateway adapter:
input 100-240v ~ 50/60Hz 2.4A
Output 18.5v -- 4.9A

HP adapter:
input 100-240v ~ 50/60Hz 1.5A
Output 18.5v -- 2.7A

The gateway has an A64 3400 chip in it vs the HP w/ a 1.5 pentium M. I know that the gateway uses more power, but is it ok to underpower it? Will it hurt the battery? BTW I know it's the adapter because I get the charging light on when I plugged the HP adapter in it for a few seconds.

You may harm both the Gateway and the HP power unit by the mis-match by trying to actually run the Gateway with ~half the power it requires.

What you may be able to do is use the HP adapter to charge the Gateway battery with the Gateway turned off - if the batteries use the same material such as Lithium Ion.

Thanks UA. I had to pull out some of my old text books to see how the volts and amps worked again. I think it'll harm the HP adapter first before the gateway notebook as the notebook is trying to draw more power then the adapter can put out like you had mentioned. What I am going to try to do is charge the battery like you advised as the batteries are the same.