WinDiff compare the contents of two files or sets of files with a graphical interface.

To invoke windiff so that you can then use menus to define the comparison, just enter
Windiff

Start>Run>Windiff>OK

Windiff can be invoked with one or two paths.The second path, defaults to the current directory.

To compare a file in another directory with a file of the same name in this directory enter
Windiff  path_to_other_file

To compare another whole directory with the current directory enter
Windiff  path_to_other_directory

To compare two directories (including subdirectories) enter
Windiff  path_to_first_directory  path_to_second_directory

To compare two files
Windiff  path_to_first_file   path_to_second_file

To get help:-open Command Prompt window and type in windiff/?

It can be installed from XP CD in the \Support\Tools directory.