Windows XP ( what can i say ? i STILL like it ) Also Windows 7 too, and i`m very proud to say that i`ve not bought a new desktop pc in over 10 years and have NEVER bought an operating system. Dumpster diving has many rewards..........i`m what`s called thrifty, or as some might say tight
I run one dual boot Windows 7 Pro x64 (upgrade) / XP Pro (OEM) for my 16/32bit needs and one with Windows 8.1 x64 Core (factory) I also keep virtual Win95 and 3.11 for when I need a nostalgia kick.