Currently using Windows 7 Home Premium 64 bit.
My laptop has Vista.
As for first, hmm, that'll be IBM PC-DOS probably about version 2, although I've tried 1.x PC DOS was made by Microsoft for the original IBM PC, then MS later sold a version of it for PC clones as MS DOS.
I've used many versions of DOS, both IBM and MS versions, and also a couple of versions of OS/2.
Favourite versions of DOS were IBM DOS 3.30 and MS DOS 5
As for Windows, the first version I used was Windows 286 (or was it 386? I forget). Anyway that was a variant of Windows 2.x
I've since used Windows 3, 3.1, Windows for Workgroups 3.11 (still my favourite of the ones that loaded on top of DOS)
After that was the usual Windows 95, 98, 2000, XP, and Vista. I had the good fortune never to have Windows ME installed on a machine I own.
Windows 7 is my favourite OS so far
