By Mark Ward
Technology correspondent, BBC News
Windows 3.x established the look of the operating system.
An application has expectedly quit.
Windows 3.x has come to the closing moments of its long life.
On 1 November Microsoft stopped issuing licences for the software that made its debut in May 1990 in the US.
The various versions of Windows 3.x (including 3.11) released in the early 1990s, were the first of Microsoft's graphical user interfaces to win huge worldwide success.
They helped Microsoft establish itself and set the trend for how it makes its revenues, and what drives the company until the present day.
For many computer users 3.x was the first Windows-based operating system they used, and the software established the iconography of Microsoft's flagship product.
As it was updated the software started to make PCs a serious rival to Apple machines, as it could take advantage of much improved graphics, had a broader colour palette, and could use multimedia extras such as sound cards and CD Rom drives.
Microsoft maintained support for Windows 3.x until the end of 2001, and it has lived on as an embedded operating system until 1 November 2008.
Windows 3.x has found a role onboard some long-haul jet aircraft.
As an embedded system, it was used to power such things as cash tills in large stores and ticketing systems.
One of its more glamorous uses as an embedded operating system is to power the in-flight entertainment systems on some Virgin and Qantas long-haul jets.
Stefan Berka, who runs the GUI Documentation Project, said the important technical innovations in the software were its extended memory that could address more than 640KB and the improvements to hardware support.
The fact that it was 100% compatible with older MSDOS applications helped too.
Windows 3.x required an 8086/8088 processor or better that had a clock speed of up to 10MHz. It needed at least 64KB of RAM, seven megabytes of hard drive space, and a graphics card that supported CGA, EGA and VGA graphics.
By comparison, the Home Basic version of Windows Vista requires a 32-bit 1GHz processor, 512MB of RAM, 20GB of hard drive space, and a graphics card with at least 32MB of memory.
Many people still rely on older operating systems.
"I haven't received an e-mail about Windows 3.11 for a long time," said Andy Rathbone, author of a Dummies guide to the software. "But I wouldn't be surprised if some people still use it."
Sales of the software still pop up on eBay, he said, but not at a price that would tempt him to part with his unopened copy of Windows 3.1.
Agent Quang from home IT support firm The Geek Squad, said he regularly encountered venerable operating systems in customer's homes but it had been a long time since he saw Windows 3.x.
"The majority of machines we see are running XP," he said, "Vista is still a bit flaky here and there and people are not comfortable with it."
But, he said, Windows 95 and 98 were still popular with some customers.
"We see them on laptops and people are unwilling to let them go," he said. "It's perhaps because in the early days laptops cost a lot more money they do now, and there's much more perceived value there."
Agent Quang's personal favourite operating system was Windows 98 because, by the end of its life, the software was so solid.
He said anyone running an ageing operating system might face problems as they try to find a web browser that could run on it and display the latest online innovations.
"We had a case a while ago a customer with a Windows 98 machine trying to view her website and the pictures were just not coming up," he said. "Eventually we had to install Netscape Navigator to get it working."
Stefan Berka said he had recently re-installed Windows 3.11 on a computer and was surprised at the results.
"Personally, I had fun at my last Windows 3.11 test installation to make it a useful desktop operating system again," he said.
"With patched SVGA driver for 1024x768 resolution, Internet Explorer 5, WinZIP, VfW and Video Player, it was still useful," he said. "The desktop was ready after a few seconds' loading time."
Said Mr Rathbone: "Windows 3.11 would still work reasonably well today, provided it only ran software released around the same time."
He cautioned against anyone considering returning to the olden days and using it as their mainstay operating system.
He said: "I wouldn't connect it to the internet, though, as it's not sophisticated enough to ward off attackers."