Changing sound output

[oldun]

I have an Acer Aspire 5740 laptop with an Acer USB port replicator. The OS is Windows 7 Home Premium.

Until a hour or so ago I had the sound coming out of the USB speakers connected to the port replicator and I could use the usb microphone also connected to the port replicator.

As I am about to take my laptop on holiday (it's worked so hard lately I thought it really deserved one!) I tried out a headphone set connected via the two jack plugs and found that it worked satisfactorily.

Now I find that the sound comes from the internal speakers and only the internal microphone works.

How do I switch between the internal and external speakers/microphone?

 

[Indigo]

Windows 7, right click the speaker icon by the clock, go to "Playback Devices" and change from the internal card to whatever you want to use. If you don't see it for some reason, right click in the white space and choose "Show disabled devices" - but simply having something plugged in should let it show up in that list.