Installed a new hard drive (thanks to those who advised me to do so). Reinstalled Windows XP and all the other discs that came with the computer. I got e-mail and internet access back, reinstalled my printer, and thought things were going well until I downloaded itunes and got a message that there was a problem with my audio configuration. There is indeed: I can't get any sound out of my speakers. . .I think they're plugged in properly (to power supply, each other, and the green plug on the back of the computer), but when I go into sounds, etc. on the control panel, it tells me that there's "no audio device." Any suggestions as to how to proceed?