China DOS Union

According to the MS-DOS 7.10 Super Boot Disk documentation

1 - You can choose the boot method at startup (Bootable media selection on boot)
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Using the famous free and open multi-system manager GNU GRUB and similar tools, together with
the related configurations I made for them, this boot disk can let you choose at startup whether to boot from this boot disk, the hard disk, or even the CD-ROM.
This way, you can keep this boot disk in the drive all the time, and use it to choose whichever boot
method you want. And even if the system BIOS does not support booting from CD-ROM, this boot disk can still truly make
booting from a bootable CD possible.
After booting, I choose CD-ROM boot in the menu, but GRUB shows ............X and then stops, and it cannot boot the Windows 2000 installation disc in my CD-ROM drive (it definitely is bootable).

What is the reason?

If I choose floppy or hard disk boot, both work as intended; only CD-ROM boot does not work.

The following is quoted from chengbing's post at 2003-10-25 12:13:22:
I choose floppy or hard disk boot, and both work as intended; only CD-ROM boot does not work.

Really? I just tried it again, and proved that it can boot from CD-ROM. But could it be that your system has multiple CD-ROM drives and the Win2K disc is not in the first CD-ROM drive, or for some other reason? Also, after it fails to boot from the CD-ROM drive, does it automatically return to the menu?

My machine is a Toshiba 2250 laptop with only one CD-ROM drive

Is it an IDE/ATAPI CD-ROM drive?