Here's a tag from one of our machines. Okuma does use an embeded version of XP. This is why it dosen't need to be updated and why the hard copy of windows comes on an Okuma branded CD. Although it may well be possible to make Win7 work, the machines are made for XP and word around the shop is that they don't intend to move up anytime soon (P300 will still ship with XP)