No. No new edition has been that backwards compatible. Having said that
Vista has some very effective options for installing and running software in
compatibility modes with legacy Windows systems. The first step in
considering Vista will be to download the Vista Upgrade Advisor from http://www.microsoft.com/windowsvista/getready/upgradeadvisor/default.mspx
Lots of XP programs just work. Others work using the compatibility mode. A
few do not work because they use software and hardware device drivers
incompatible with Vista (vendors will probably provide these by release).
There are a few additional considerations on 64bit Vista, but even there
most programs work under the Windows on Windows64 emulation layer.
