Please where can i get the origanal MS-DOS, I need it.
Not mandatory but botting from a floppy is best.
You can get lots of MS-DOS boot disks here.
I doubt you really want the original MS-DOS -- DOS 1.0 didn't understand things like 1.44MB floppies. 
Win98 had a genuine MS-DOS underneath, which makes it probably the newest version of 16-bit MS-DOS except for the crippled version underneath Windows ME.
There's also FreeDOS, which is MS-DOS compatible. I've seen board manufacturers use it for BIOS upgrade disks and the like, so it must be pretty stable.
With Windows XP, you can right-click on the floppy drive and one of the options is to format the floppy. A window will pop-up and it has a check box for "create an MS-DOS setup disk". If you remember the old "setup" command under DOS, that is basicly what happens. The resulting floppy can boot up and run command.com, but nothing else is on the floppy. I did that, and from my MS-DOS prompt, I typed "ver". Oddly enough, I got:
Windows Millennium [Version 4.90.3000]
I have to believe that this represents the latest version of MS-DOS.
DR-DOS is still with us. This is an option if you want to buy a supported product. Apparently DR-DOS forked at some time in the past. There seems to be a free open-source version DR-DOS/OpenDOS. So there are two versions of DR-DOS available. And there is a very ambitious project called GNU/DOS which is a basicly a distro of FreeDOS.
The ME boot disks may be the newest but I don't reccomend them. Microsoft gutted nearly everything important. Things like "format" return obnoxious messages about how everyone knows you aren't supposed to use a DOS prompt these days.
dear sir i want to download the ms-dos from your site.i want ur real help to do this activity.this is amit agarwal posting a letter type message
Go ahead and do so. Plenty of links to plenty of boot disks in this thread.
Those guys from India and their translation programs are driving me crazy. 
Ok, you caught me on violation of rule (14).
No, it was for the rule 1st and 2nd. So please be patient. I have many Indian friends who can speak better English than Germans.