-- Disk - Vista is more disk intensive. Older machines have 4200RPM disks and Vista is designed for modern computers. While desktops might meet the specs they may not perform well. A 7200RPM disk is okay.

-- Windows Explorer - Finding things like a file menu is sometimes challenging. It's not bad, it's just different. The places where files have lived have changed. I want to see everything in the operating system.

-- Administrator account - It is disabled in Vista, and it's not an option. There is a registry hack to log on as an administrator. It is a good thing but all these prompts pop up.

-- User account control.