I've read the advanced manual online in addition to find a solution for my problem. I've bought my POD recently and since I have no amplifier I would like to use it on PC with USB connection, but there was only an option to send the signal from the HD500 to the speakers on Windows 7. Does that mean I can't use it like that on Windows XP or there is a solution for that?
You can take the analogue outputs from the POD and feed them to the inputs of your computer audio system and use the computer's speakers that way. This won't utilse the USB connection between POD and computer however. It is definitely preferable in many ways to use the HD500 as your sound card and to connect suitable speakers to the POD's outputs instead of using the computer's inbuilt audio system.