Windows XP was Microsoft's operating system from 2001 to 2014. This is definitely the longest lived OS in MS history.
My mom was working for a public school when I had my first encounter with XP. Her computer had the default Luna theme (blue) which was a lot different from the Windows 98SE we had at home.
Several years later, in 2006, I started working for my school's computer department. I was making above minimum wage (I believe I was making $8 or $9/hr at the time) but I had a budgeted number of hours for the summer. This was the summer that I built my first computer. When I built my computer, I built it in stages. I calculated that I was making $1500 that summer and so that was my total budget. I purchased XP Pro OEM.
When XP was first released, Home Edition was green and said “Home Edition” and had a green loading bar. Professional Edition was blue and said “Professional” and had a blue loading bar. With Service Pack 1, Microsoft changed the boot screen to just have the Windows XP logo and a blue loading bar. One of my online friends was mad because seeing “Professional” when booting made him feel special.
I loved the Microsoft Zune theme.