dos update instruction

I am unclear about what exatly you are asking. Here is a great page that covers the windows 2000 version of DOS. It has alot of good info and should answer your question.

http://www.pcworld.com/howto/article/0,aid,61687,pg,5,00.asp

Windows 2000 is not a DOS based operating system.

You can open a DOS window and run some DOS commands.

Some DOS programs will run on a W2K system in a DOS window.

Very few Windows updates fit on a floppy disk anymore.

Besides, if you were to boot from a DOS floppy disk, you would not be able to access the hard drive on most W2K systems. The file system on a typical W2K hard drive is NTFS not FAT.
DOS can only access a FAT partition.

Now, you can create a DOS boot floppy from W2K.
Right click on your floppy drive and select Format.
There is an option to create a MS-DOS boot floppy.

Chas