I have and old laptop that has been formated with dos 7 for windows 95
When I tryed to install windows 3.1 on it
I found out it had the wrong dos
I got hold of dos 6.22 but when I have inserted the disks and run setup it also says incorrect dos
How do I remove windows dos so I can install dos6.22
PLease

You can find a low-level format util and NUKE IT INTO THE GROUND and then boot from the DOS 6.22 disk.
You might be able to install DOS 6.22 over DOS 7 provided that it's not a FAT32 partition.
Anyway, if you don't give a crap what's on the disk (or if you just need to back up a couple files, do so), you just want 6.22, then boot from the DOS 6.22 disk, and quit setup. Run FDISK and dump the main partition
and make a primary one.
(I'd leave the others where they are if you didn't know they existed in the first place, like on Compaqs it has a special bootable partition that the Setup utility resides on)
Then reboot with the DOS 6.22 disk and you should be fine from there on.
If you're using FAT32 and you want to keep what's on the drive...................have fun. Get a LOT of floppies. Or a ZIP drive or something.

Use fdisk.com from DOS 7. Remove the partitions on the drive. That should remove everything. Reboot with a DOS 6.22 boot disk. Run fdisk.com from DOS 6.22 and create a primary DOS partition. Reboot. Run format.com c:
and format the hard drive. Then, it should be ready for you to install DOS onto it.

Fdisk.com is different from DOS 6.22 to DOS 7. Use DOS 7's fdisk to remove the partition and use DOS 6.22's fdisk to create the new one.

FDISK from 6.22 reports FAT32 as Non-DOS. You can still remove the partitions though.

You could not go back to DOS from Windows 95. The problem was in the master boot record. Assuming everythibng is fat16, enter FDISK /MBR, and then try to install DOS. If that does not work--I have never actually installed this way, you can format with MS-DOS ver 4.00. I have done this.

What?!
are you guys nuts?
you DON'T need to wipe out the
whole flipping drive just to add a new
(or old) OS!! just some free space
and some utils like some of these:
cfdisk (much better than dos fdisk)
fips.exe (splits fat partitions)
system commander (boot manager that can HIDE
one OS from another - makes booting 4
versions of dos 3 versions of windows and
5 flavors of linux MUCH easier)
partition commander 6 (make many types of
partions AND MORE IMPORTANTLY
it can RESIZE them!!!)
there are many free utils that can also
do these tasks from windows "dos mode"
there just not as user friendly/well known.
if you don't have free space/don't care about
files then try burning a backup
to cd(s) then make 2 primary partitions
(but not with dos fdisk it will refuse
BUT..^_^.. cfdisk will do it)like this:
pri_1=35mb to 500mb for ms-dos 6.22
pri_2=800mb to 30gb for winblows
extended=all left over space(see below)
logical=800mb to 30gb(at least 1)for data
now just make the one you want bootable by
defualt the "active" partition and be sure
the one being installed thinks it is
"active" during the install (you gotta keep
changing it) then make sure you have a boot
manager that can run them both (like system
commanders "hide") it can be done manualy
by changing witch one is "active" with fdisk
just DON'T set them both "active"!