Simplify the following text for a Grade 4 native English-speaking person.
Original: PC World also named Windows 7 one of the best products of the year . In its review of Windows 7 , Engadget said that Microsoft has taken a `` strong step forward '' with Windows 7 and reported that speed is one of Windows 7 's major selling points particularly for the netbook sets .
Simplified: There are six main editions of Windows 7 .