I used format a:/s to make a blank boot disk. It seemed to have only one command.com on it, and then after I ran command, two more files appeared: io.sys and msdos.sys.

They just showed up by themselves.
So are all drivers added on top of this? Do I just create a config.sys and configure the drivers in it?
Also, when I boot the machine with this disk, it shows the following:
Starting MS-DOS 7.1...
Microsoft(R) MS-DOS 7.1
(C)Copyright Microsoft Corp 1981-1999.
A:\>_
It seems to write that by itself. Is there any way not to have it? Or can I edit it myself?
And also, thanks to all the enthusiastic experts here for helping...
一切都会好起来的