unix to windows conversion

I have a pentium scsi with unix installed. It used to be a workstation in my former workplace. I'd like to install windows for my sons use but don't know unix and it's pw protected (don't know the pw). How can unix be deleted and windows put on?

You should just be able to put a windows CD into your drive and boot up off of it. Windows will happily reformat your drives for you...

Before you can remove the UNIX, re- partitian again or else the windows can't detect the partitian. It will state that the previous partiton - NON-DOS.
Remove the Non-DOS partitian and make the DOS type partitian and reboot before the Windows setup.