That looks nothing like a OSX, like I said, it is the Phone 7 interface. For your reference I have included a link to Google with screen shots of OSX
mac osX - Google Search
Now look at that, you ain't paying attention again. 3/4 of the way through the video that you provided what do you see. Oh my gosh a task bar and start menu. I know you are going to say you didn't see it, then ask where is it, spoon feed it to me. So I guess I will have to. The part that he is talking bout using existing apps, and brings up Excel 2010. At the bottom of the screen, there it is, task bar and start menu. Then not only that I found the Windows Explorer and Control Panel already in the video. If you need another spoon feed answer, it is at the beginning. When he shows the tiles for the first time, middle row all the way to the right, Windows Explorer, green tile with the Sprocket, Control Panel.
Yea, so you bought cheap out of date computers and want them to last a very long time. I guess if you call three years a very long time, then they should do fine for that. Any way, I have to go to work.