New Imac and external drive problem

Hi

I've been waiting to make the switch for months now and now it's done.. got myself a brand new 20inches Imac yesterday. While waiting for them, I prepared my switch by formatting my external harddrives in FAT32 instead of NTFS. But now, i plug in the drive in the usb port and nothing happen. Isn't it supposed to appear on my desktop? on my windows laptop it still works fine.

Also, since the case is FW and USB2.0, if I plug it in FW then my Imac recognize it no problem!

Thanks

Does the drive have an external power supply? If so, it needs to be plugged in to use the drive with USB. FireWire is 'Bus Powered', meaning it can run without an external power supply (with some limitations). If you don't have a power supply for the drive, and still want to use it with USB, you'll need a USB 'Y-Adapter' that is essentially two USB plugs to the computer to supply the extra juice.

it has a power supply I tried it through a usb hub as well... the ipod, the usb key are all working but not this disk, but it's working fine on my laptop... weird.