According to these operating-system statistics, Windows 7 is the world’s most popular operating system, and overtook Windows XP in August 2011. Since then, its lead has grown, and it’s now run by 48.7% of users.

The Windows 7 predecessor, Windows Vista, never rose above 18.6% of the market, its peak in October 2009, and now enjoys a mere 4.5%, while Windows XP has fallen to 30%.

Let’s take a minute to analyze why Windows Vista failed to take control from Windows XP, and why Windows 7 managed that same feat, a mere 22 months later.

Why Windows Vista Failed

1. PCs weren’t ready.
Windows Vista was envisioned as an broadband-ready Windows operating system with advanced graphics and security … a quantum leap from Windows XP. Only problem was, in 2007, PCs weren’t powerful enough to handle it. Many PCs shipped with Vista that just couldn’t handle the software. Lack of RAM and video hardware made slowness a huge issue, where XP still went fast.

2. A lot of crash bugs.
Early versions of Vista were riddled with technical problems and crashes. Downgrading from Vista back to XP was a very popular move (which I did). Fixes didn’t come out for some of these errors for some time.

3. XP was too entrenched.
In January 2007, when Windows Vista came out, Windows XP had a massive 76% user base. It was, by far, the most popular operating system up to that time. Breaking people of that habit was an insurmountable problem. Other than specific games requiring the “Games for Windows” interface present only in Vista, there was no compelling reason to upgrade.

4. Drivers didn’t work.
My mother-in-law had an all-in-one Epson printer that came with her PC when she upgraded from XP to Vista. One problem: Epson didn’t bother writing a Vista driver, and the XP driver refused to work. Her printer became a very large, very expensive, very heavy doorstop.

5. User Account Control.
User Account Control is the popup that appears in recent Windows operating systems, whenever you perform a function that modifies the PC in a significant way. UAC wasn’t in XP, and the introduction of frequent popups, though important for security purposes, increased the level of annoyance to an extreme degree.

Why Windows 7 Succeeded

1. PCs came a long way in 22 months.
The price of memory (RAM) and mass storage (hard drives) plummeted between January 2007 and October 2009 (and continues to fall). For the first time, people could afford machines that stood a chance of running a graphics-intensive operating system like Windows 7. Also, a much higher percentage of users had broadband Internet, and at faster speeds.

2. Windows 7 was stable.
Though crashes, lock-ups and Blue Screens of Death (BSoDs) were common in the early days of Vista, no such troubles plagued the majority of Windows 7 users. Plus, it started up much faster, which was a big selling point.

3. Windows XP was loosening its grip.
By October 2009, Windows XP usage had dropped to 63%, compared to 18% for Vista. The time was right for a new OS to take over, and it happened very quickly. By January 2010, Windows 7 had 11%. By July, 21%. By January 2011, 31%. The numbers kept rising for Windows 7 and kept dropping for every other version of Windows, finally. It’s a good bet that Microsoft was relieved that they didn’t have to rely on a user base that still ran a 2001 operating system.

4. Manufacturers got the driver issue right.
By getting Windows 7 in the hands of businesses faster, they were able to make drivers available on day 1. And most drivers written for Vista carried over, too.

5. User Account Control was dialed back.
The standard UAC setting on Windows 7 was dialed down a notch. No longer would the screen grey out and a prompt stop you in your tracks over every little thing: only important things.

There are many more reasons why Windows 7 is better than Vista,  right from marketing, to the Quick Launch Taskbar, to built-in disc burning, to widespread corporate adoption, and so on. With Windows 8 on the horizon, it remains to be seen if Microsoft has another hit on its hands, or just another expensive failure.