From the sticky:
http://www.emutalk.net/chankast/20636-chankast-f-q-before-asking-anything-read.html
Q: How do I run games?
A: The emulator supports only selfbootable backups, original and non-selfbootable disks will not work.
IMPORTANT NOTE: Running CDs is not generally recommended, prefer using CD images instead.
Q: Every time I try to run a game Chankast recognizes it as a music CD or thinks that there isn't a CD in the drive, why?
A: This can be caused by the following things:
1: You're trying to run an original Dreamcast disk (GD-ROM). These disks are not supported by the emulator.
2: You're trying to run a game using the "XXX CD-ROM Interface" on Windows 2K. This Interface is not supported in Windows 2K so you MUST use the ASPI CD-ROM Interface when using Chankast on Windows 2K.
3: You're trying to run a non-selfbootable disk. Either use a tool to make your game selfbootable or use the Utopia boot disk.
4: You have selected the wrong drive from the drive configuration of the emulator. Run the emulator, go to "Options"->"Configure Drive" and select the drive where the game is.
Unless I'm misunderstanding you - your trying to run a GD-ROM in an unmodified CD/DVD drive. It just doesn't work - sorry man.
If you are trying to run a CD, I'll try to help you configure chankast and/or rip the CD. CD's are ones you've burned, not games you would get at the store.
