The system is 98SE, the hard drive is a Maxtor, I don't remember the exact model, 20G. The system works completely normally. I downloaded a hard drive diagnostic tool from Mydrivers -- Maxtor's latest MaxBlast Plus 3 application, latest version 3.6. Following the instructions I made a disk. After booting from the disk under DOS, it shows BAD OR MISSING COMMAND INTERPRETER PLEASE ENTER A VALID FILENAME (e,g c:\command.com). Entering c:\command.com and pressing Enter gives no response. When reinstalling 98SE there are also error prompts, and when it's serious it can't be installed at all. After booting with a newly made boot disk, doing SYS C: also gives an error prompt, and DIR/A shows nothing at all. But installing XP works normally. Can any experts explain what's going on? Is there a problem with MS-DOS?

