Yes, to kernel 2.4.26, but when I try to boot to that kernel I get "kernel panic: VFS; unable to mount root fs on 21:06"

Mepis comes with a live CD sort of like Knoppix so I booted that to 2.4 and I am typing this from my network internet connection.

So it appears that the kernel is the problem.
Now the question is should I just reinstall? I was hoping to avoid that. The problem may be that I have Win4Lin installed on kernel 2.6.7. I don't know if kernels are switchable after application installations or not. When I was testing Mandrake I installed the test version of CrossOver Office and when I switched kernels it wasn't available. Also, what is the functional difference between the kernels. Obviously 2.6.7 has problems with my network so I must do something, but what will I be giving up if I go back to 2.4? 2.6 was the default, so I assumed it was "better". I noticed that Mepis now has 2.6.9 as the release version now. I wonder if that would work or if I would get a similar kernel panci with it?
Thanks again for all the input.