i don't know but the last time i've tried kega it wasn't even able to run sonic-cd!
then i felt like it got discontinued, renamed or whatever (like retro-drive ans stuff) and never found a newer release. soon after that i've switched over to gens and i'm quite satisfied with it. it supports genesis, sega-cd and also has a very nice 32x support. also it does work with games in your secondary cdrom - unless your first drive has a cd inserted at boot time.
you should try wgens version 2.11, runs nearly anything 16bit-sega related.
wonder is right, last I heard the Kega author had a hard drive failure and lost the source after like 2 releases, so it is now discontinued. Gens works great for pretty much everything, except the 5 32X-CD games.
the thing is that you need to have a compatible aspi-driver installed. not only should it work with your kind of drive but also with gens. as there are so many different aspis out there you need to cut your way through the jungle first. as the gens author says in the manual: no aspi, no cdrom support.
usually windows comes with some sort of aspi and it sometimes is sufficient sometimes not. just try severel drivers if the dumb one by bighard doesn't work.
oh yeah, i almost forgot: is the drive scsi or not? if so, new problems could arrise.
I've tried Gens, and pretty much every other emulator I could find and i've used force ASPI to try and get it working, but with no luck.
The problem is that it runs under win98 using my 2nd CDROM, but on XP, the emulators don't recognise my 2nd CDROM, despite the pressence of Force ASPI. I have no idea why the games don't run on my first CDROM, go figure.