How can Parallels claim that an OS is supported when drivers are unavailable?

How can Parallels claim that an OS is supported when drivers are unavailable to make the VM work?

I wanted to install Win 98. But there looks like there is no sound driver available. Even the supplied network driver fails. Not to mention the two other unknown drivers for it.
I purchased this specifically for OLD operating systems. Not everyone wants or needs Windows 8. I would even like to install dos with sound, but from what I have been reading, it will have the same issues as my 98 install. I've wasted a fair amount of time since the purchase of this software trying to make things work.

Needless to say, I am let down by my purchase. I guess maybe the free VirtualBox would have been a better choice.

Brian