IT has to ask a lot of questions to figure out the best way to migrate to Windows Windows 7, due to ship on 22 October, has gained good reviews as the OS that Vista should have been. And the large percentage of businesses that have held onto XP rather than go to Vista - about half, according to Gartner - are no doubt planning to migrate to Windows 7. But Microsoft may be making it harder and costlier for them to do so, notes Gartner analyst Michael Silver. "It's a disaster waiting to happen," he says.