Are you trying to do this via bluetooth ? - If that is the case then do you mean you can not pair the two devices..
If the speaker is not discoverable by your computers bluetooth then reset the bose speaker by holding down the mute key for 10 to 12 seconds.. after the device powers off then power it back on.. This may solve the issue sometimes bluetooth devices get confused if they were previously connected to a prior device.
Which model Bose speaker do you have?