I had sound on computer when i put on windowsxp pro sound gone

If you mean that you cant get any sound on your computer
control panel sounds and audio,volume you can adjust the volume or
advanced,speakers select appropriate speakers or
audio you will find 3 drop down lists make sure you have selected the right speakers or control panel,administrive tools,computer management,device manager scroll to sound,video and game cotrollers could be a yellow question mark? right click to re-install drivers
hope this helps