Twenty years ago, amid great fanfare, Microsoft released Windows 95, its feverishly anticipated new operating system.

The launch was hyped by a $300 million marketing campaign, including a “cyber sitcom” showing off the new features. Friends stars Jennifer Aniston and Matthew Perry made cameos. Commercials for Windows 95 played The Rolling Stones song “Start Me Up,” heralding the introduction of the now-iconic Start button.

In addition to the Start button, Windows 95 introduced the task bar, and added support for filenames up to 250 characters (a thrilling feature at the time) and “Plug and Play” support for installing new hardware.

Many electronics stores held midnight launches for the product, with thousands of people waiting in line to be the first to get their hands on the operating system.

The release was a tremendous success. Microsoft sold 7 million copies in the first five weeks, and Windows 95 was soon the most popular operating system on the market.