Why compare only to Windows 2000 features As this issue has clearly caused quite a bit of confusion I ve decided to address it here Windows XP is in the unique position compared to all other Windows releases I can think of of being at the convergence point of two separate Windows product lines that of Windows NT and the old MS DOS based Windows 9x However the core code in XP is based on the former and not the latter hence XP has an internal version number of 5 1 while Windows 2000 has one of 5 0 among numerous other things A list of every single feature included in Windows ME the last of the MS DOS based versions but not in XP would be quite long indeed and also quite pointless because it would be comparing operating systems of two very different architectures There s also the fact that comparisons between the other List of features removed in Windows articles and this one would actually be made far more difficult