Windows Longhorn build 4051

This Milestone 7 build was distributed at PDC 2003 in Los Angeles, California. This build, for its Professional version has a 32-bit and a 64-bit version. The 64-bit version is not overly different from the 32-bit version, but it has a new setup style and several apps including IE 6 have been optimised for 64-bit (often, the 32-bit ones do not run) The Check/Debug version is not known to run.