When you say plug the Bluetooth in, I assume you are referring to a Bluetooth dongle for which you have to add the drivers? Since you obviously know how to set up Bluetooth, does it appear to be installed correctly and on the Emachine?
Do you have the Dongle in a front USB port or fairly close to the headset for testing?
You normally add Bluetooth devices through the icon in the hidden icons area, so if you start that utility looking and the headset set as discoverable, it still can't find it?
Do you have one of the other devices you use the headset on in the local area?