i'm still in my childhood, but in my early childhood my dad used to have an, at the time, loving BEAST computer. 16 gigs of ram w/ NVidia G-Force series graphics. We had more than 10 operating systems installed on the computer, and I spent a lot of time on MS-DOS and DR-DOS.
god the memories ;(

DOS was all I was allowed to use, due to the fact that I only knew how to make text-files and folders, so I could do no real harm to the computer.
When I was 5, I used Linux for the first time, I think it was Devil Linux.
And finally, when I was 6, I used Windows for the first time. I fell in love with Microsoft operating systems until Windows 8 was released. forget W8.