Thanks to a new update for Windows 7, just about anyone should now be able to run old software through Windows XP Mode—provided they have Win7 Professional, Ultimate, or Enterprise to begin with, that is. Microsoft blogger Brandon LeBlanc broke the news on the Windows Team Blog, saying the new update strips away the requirement for hardware virtualization capabilities.
When Windows XP Mode first appeared in beta form, we pointed out that the lack of support for both Home editions of Windows 7 and processors without virtualization acceleration would reduce the software's potential user base quite a bit. At the time, Intel's processor lineup was a patchwork of offerings with and without virtualization capabilities, all at different price points. Intel has since addressed the problem somewhat, but some of its older CPUs still lack the functionality—even speedy quad-core ones.
As LeBlanc states, of course, Windows XP Mode will continue to take advantage of virtualization features in processors that do have them. In those configurations, hardware VT support presumably induces a speedup.
You can grab the update right from the plain Windows XP Mode download page. Simply select your edition of Windows 7 and your preferred language, then click the "Windows XP Mode update" download button. Microsoft confirms on the page that this patch "enables Windows XP Mode for PCs without Hardware Assisted Virtualization Technology."