Who told you that you need a FAT32 partition to use a command line (DOS or otherwise) and "do stuff in DOS"? You say that you can't "open a dos window through windows". What do you mean by that?
There are two ways to get a command line in WinXP, by invoking CMD or by invoking COMMAND. You can do that by opening the Run dialog (Start | Run) and typing either CMD or COMMAND, and then hitting the Enter key. CMD gets you the WinXP command console. You can run many types of DOS programs in the console. COMMAND gets you directly into a command line that runs inside a DOS emulator under Windows.
If you need true DOS, then you need to boot from a DOS boot floppy. But you won't be able to access the NTFS partition from DOS, not without a third party utility.
Give us a little more detail about what your system is or isn't doing and what EXACTLY you need to accomplish, and maybe someone will be able to help.
- Collin