Uninstalling win2k?

Well you can either use a bootdisk and do an fdisk and delete the partition.  Or you can just run the install for the Linux OS you are going to install and run fdisk from there or if you are using a graphical Linux install at some point it should prompt you to choose a partition or delete a partition and you just have to choose the Win2k partition.

Dis

Well it looks like both my win98 and win2k are installed in the same C drive.There is a directory "Windows" which is win98 and another directory "WinNT" which is for win2k.But they both are in same C drive.So is it possible to remove win2k alone using fdisk? Thanks.

I think the problem might be that you are dual booting and that the OS boot loader is NTLoader.  I think if you remove Windows 2000 you will have problems booting to the OS.  I would suggest installing Linux first hopefully on another drive or partition and then use that to boot into Windows 98 and Windows 2000.  Then from Windows 2000 remove all programs...then go to Windows 98 and delete the Winnt folder and the Documents and Settings folder and that should remove most of the Windows 2000 files.  The removal of programs from within Win2k should have gotten rid of most of the files in the Program FIles folder that belonged to WIn2k.