What do you mean by, Download Xp and then you loose your sound. Is it simply that you've lost the sound operation, once you've installed XP PRO?. . If so then, you got to install the correct drivers that came with your sound device.(Sound Card! i.e. Creative). . Or you could try going to the Control Panel-> Sound and properties, and then untick the box that reads "MUTE". Now it should be ok!. . Still if this doesn't work, i'll say you better go check your sound card, if PCI, and get it tested. If Integrated you may have it tested but if results are negative, you have to replace it with a PCI card. When doing that makesure you Disable the In-built Sound Device in the BIOS CONFIGURATION.. . Best of Luck!