Have speakers but no sound.computer does not know...

Well, they both should work if you go to HP's download and support website and download the appropriate drivers for your associated hardware. Find out what hardware you have by downloading a marvelous freeware program called Belarc advisor. it will list all hardware, software, versions, keys, etc. When you installed the XP frm Siemens, it likely installed drivers compatible with the model it was designed for, rather than your Fujitsu. First, go to control panel, click Hardware and sound, then see what audio device it thinks it has. If it isn't the one your motherboard was designed for, find out what motherboard you have with Belarc, then download the audio device which works with it at the HP website. Whew. Let me know how it goes.