Is there a cricket in my machine?

Hello everyone, I'm about 3 months into the Mac experience. I had a 1.8Ghz 1GB Ram machine, then I upgraded to a dual 2.0Ghz 2GB Ram machine.

I have the same graphics card in both machines. Now I would of course think that my new machine would be much better/faster, and so far so good. However, when I went to play my new online game on THIS NEW machine, as soon as I start playing I get a crazy high pitched bird/cricket sound coming from inside the machine! As soon as I stop playing the game, the sound stops.

Any ideas? I kind of worry when buying a used computer, I mean it's in good shape and not too old, but it concerns me nonetheless.

Thanks all

I can't say that being online, whether gaming/browsing would cause such sounds from your computer.....

Is there any consistancy to this....

are you saying it is the same exact graphics card you had in your last one or you purchased the same one and have it in both machines??? reason i mention is maybe your graphics card fan is messed up and causing the n oise.... see if it does anything similar while watching movies or something
-chris

hey thanks for the replies. No it's not the same physical graphics card, but the exact same model. I haven't noticed the sound when I watch movies, but granted I haven't done too much of that. The sound starts and stops like clockwork whenever I start or stop playing the game.