As a fan of old software, I was pretty bummed to find that you can't run Program Manager under XP SP2.  However, my dismay was tempered when I discovered that MS-DOS Executive, which goes all the way back to Windows 1.0, not only still runs on XP, but is actually available for download fromWinSite! Oh, and if you want to relive those thrilling days of yesteryear, when Windows 1.0 was the hottest thing since the Apple Lisa, be sure to check out this recently unearthed archival file of Engadget from 1985!