Using two or more partitions would be needed more so when using two 9x OSs. Since my setup was 98 SE and 2000 pro I placed everything ont he one partition. IE's defalt install dir was Program Files in both 98SE and 2000 pro. Because of this when I upgraded my IE in 2000 pro to 5.5 sp2 it overwrote the old IE 5 files that 98SE shared with 2000 and 98 was no longer able to use IE. To solve this I just installed IE to a different dir ("Program Files 98"). Now they are separate and both function properly.