You get it from Lenovo. You call their customer support line, say you would like to obtain a set of restore media for your system, and they'll take down some info and set you up. There may be a small fee involved for the cost of the media and shipping, but it will be considerably less than a retail copy of Windows. The basic procedure is the same for any manufacturer BTW, just substitute Lenovo with say Dell or HP.
I have recently bought a Lenovo ThinkCentre which came with a clear. wiped hard disk and Windows Vista Product Key sticker on the back of the PC, which I believe is genuine.
My question is where can i get the Vista source to re-install Vista on this machine? I am really hoping that I do not have to purchase a copy of Vista (or windows 7) as this machine was previously already correctly licensed.
Sorry if this is a much-repeated question, I looked through Tips and Tricks and some pages of the forum but didn't come across this particular wrinkle.