Win 2000 Pro

I am considering upgrading my soho computer from W98 SE to W2K Pro. Two concerns:

1) I understand W2k uses the NTFS file system. Will I face conversion problems from the FAT32 file system W98 uses? If so, how do I handle it? Will I need to re format my HDD? What about my existing files on the HDD?

2. Does W2K support DOS commands? If not, what are the work arounds?