Windows NT 3.1

Microsoft's first version of Windows NT, released in September 1993, price UKP 395, after having been in beta-test for as long as anyone could remember.

The person responsible for VMS on the DEC VAX [who?] was also responsible for Windows NT. Incrementing each letter in VMS yields WNT.

http://win2000mag.com/Articles/Index.cfm?ArticleID=4494.