Question: What is the oldest version of microsoft windows?
Answer: Windows 1.0
Disambiguated questions and answers: question: What was the first ever version of Microsoft Windows?
What was the first version of Windows that was its own operating system?
What was the first version of Windows that was a fully 32 bit operating system?
answer: 1.0
Windows 95
Windows NT 3.1
Natural Questions answer: Microsoft Windows , version 1.0 (from the Wikipedia article "History of Microsoft Windows")