Try
visiting my FAQ, click on Troubleshooting > Sound Problems, and then in particular try the suggestion about turning down hardware acceleration in DXDiag. If that doesn't help, then turn the hardware acceleration back up. Also try turning off Hardware Sound in the game launcher by adding an X beside it.
If either of those work, then there's possibly something wrong with the driver for your sound chip. Do you have any other games installed, and do they work okay? You hear sound effects and music?
Again, you can also try running the WMFADist program in the Tron 2.0 folder. (Though if you have a 64-bit version of Windows 7, it won't work.)
If the problem is just with Tron 2.0 and not other games, I don't know how far you'd be willing to go to make it work. But I have heard from other players that the drivers from Realtek don't work very well with Tron 2.0, and that using the sound drivers for your Realtek chip that are built-into Windows work better.
If you'd be willing to try that: go into the Windows Control Panel, click on the Programs and Features icon, look for an entry for Realtek, and then uninstall it. After uninstalling, download and use the program
Driver Sweeper to get rid of all traces of Realtek's drivers. Then reboot the computer and let Windows install the default Microsoft drivers for the Realtek chip.
Later, you could try reinstalling
Realtek's own drivers again if you wish. Maybe a clean reinstall will help get them working properly again. Though as I said before, some people have told me Realtek's drivers don't work well with Tron 2.0.