A DOS boot disk fixes absolutely Nothing.
If you want to do a Scandisk from DOS then you need the Scandisk.exe file on the disk.
Same with any other program you want to run from that disk.
Now, there is one exception....of course...
If you have a program on your hard drive that you want to run, like Scanreg.exe, they you can run it from your A: prompt if you know the path to it. Something like this:
You just have to know where the command resides on your hard drive to run it from the A:\>
Now, telling us exactly what it is you're trying to do, would help immensely.
If you'd like my own DOS boot disk, then go to my Download Site
and download wnMEboot.exe
Just run the file and it will make for you a very nice Boot Disk, complete with full color menu.
It's actually Windows ME and NOT 98, but that's OK. It will work just fine on 98, 98/SE or ME.
With it you can run a scandisk, or run "Scanreg.exe /restore" or do some serious cleanup of your hard drive with my "Hoover.bat" program.
It's all Menu driven.....nothing to type.