"First, Windows 7 is no more secure than Windows has ever been. Is it better than Vista? Sure. Is it faster than XP? Well, not so much. Does it run a ton of popular applications? You betcha. But, is Windows 7 still prone to an endless array of malware programs and stuck with a pre-Internet security model? Yes, yes it is...
"2) Cheap
"I'm also cheap. I use older computers until they fall apart underneath me. I have Ubuntu 9.10 working great on a 1.4GHz Pentium IV HP with 512MBs of RAM which I got back in 2000. I could no more get a decent version of Windows 7-Home Premium or above-to run on that box than I could get my old Toyota RAV-4 to break 100 MPH on the highway."