Can`t understand how flash player could have removed your sound device, but you need to go into device manager to try and reinstall it. If you`re on xp click my computer- view system info - hardware - device manager.
Look for your audio in there, there may be a yellow question mark next to it. double click and follow instructions, windows will try to find the driver.
Do you have a driver disc, that came with your computer? If so insert it and follow instruction to install from your cd drive.