mgary welcome to the forums.
What you're running into is old hardware with no support for new operating systems. In your case it is the old C-Media audio chip that has no support any more and no driver
even available from C-Media.
One thing you can try (short of buying a sound card that does have Windows 7 support) is try the XP driver from here, ASRock > Products > Motherboard > P4VM800 > Download
and install it in Compatibility mode, Compatibility Mode
Just make sure to uninstall any previous driver that you have installed before trying the above.