MS has about some version of it's os on about 90% of all the personal computers. That is hundreds of millions of installations. There will always be people that have some combination of hardward and other software that ms did not anticipate and will cause the operation system to do something wrong.

At the same time lots of organizations will delay implementing a new ms operating system. It generally has a lot more to do with their technical staff being familiar with the new software or their in house applications not being ready for the new os than problems. Though some will complain about the problems in the new os as well.

That is not a new phenomenon. It has been happening since windows 3.1. As every version has matured the problems have declined. Simply because of the sheer volume of installations problems get more press that the other os'. For everyone with a problem there are 10s of thousands that have no problems at all. Vista is close to reaching the 100 million install mark. Obviously it is not a crisis.