China DOS Union

My XP is installed on drive C, formatted as FAT32. I installed MS-DOS 7.10, but during installation it couldn't see drive C? But drive D, which is also formatted as FAT32, can be seen.
And after I installed DOS to drive D and set D as active, after reboot it actually couldn't get into XP.
If I set drive C as active under DOS, on reboot it says the autochk program cannot be found, and then it can't get into XP.
Sigh, what exactly is going on here? Experts, please answer, 55555555555555555

I didn't quite understand it, so I'll briefly say what I think… 1. The general order for installing operating systems is: from lower versions to higher versions. In your case specifically, it should be DOS first, then XP. They can coexist / achieve dual boot. 2. Your XP is on drive C, and then you formatted drive C again (?)—wouldn't that wipe out XP? My experience is that if you absolutely must add the DOS 6, 7, etc. boot loader to drive C where XP is located (taking DOS 6 booting as an example), then you need to ⑴ back up the current XP BOOT (DOS boot sector) in advance, ⑵ after booting DOS 6 from CD or floppy disk, use the command sys c: to transfer the system to drive C, ⑶ back up the DOS6 BOOT again and rename it bootsect.dos and store it in the root directory of drive C, ⑷ then restore the backed-up XP BOOT, ⑸ next use a text editing program to add a line at the end of C:\BOOT.INI: C:\ = "DOS 6" ⑹ after saving BOOT.INI you can test whether dual boot is OK…