Tech support firm iYogi flags issues users encounter when moving to Windows 7 from earlier versions of the operating system.
At the top of iYogi's list is failure of an upgrade from Vista with a "62% completed" message accompanied by a system hang. In that case, the user can reboot and the system will roll back to Vista, or the user can follow detailed instructions on iYogi's site in order to successfully complete the upgrade. Users' second most common problem occurs when the PC's DVD drive is no longer visible, even following a successful installation of Windows 7. See the complete article for the entire list of problems and tips for fixing them.