People dislike Microsoft's (MSFT 0.37%) Windows 8 so much that over 1 million users signed up to beta test an early version of its replacement Windows 10 operating system in the first two weeks it was available -- despite the company encouraging them not to do so.

The Windows Insider Program offers open enrollment and does not check credentials before letting users install the early test version of Windows 10. The company does, however, make clear on the program's Web page that the current iteration of the software is not for everyone, stating, "If you're a PC expert or an IT pro, come on a journey with us and be part of creating the best Windows yet."

Microsoft offers a further warning when you visit the "Before You Install" section of the site.
Unexpected PC crashes could damage or even delete your files, so you should back up everything. Some printers and other hardware might not work, and some software might not install or work correctly, including antivirus or security programs. You might also have trouble connecting to home or corporate networks.
Basically, Microsoft couldn't be any more clear if it put up a skull and crossbones or placed the Windows logo inside the anti-smoking red circle with a slash through it. That did not stop plenty of people from trying out the new operating system, and it seems likely that many of those early adopters are not "PC Experts" and "IT Pros." 
 
The hatred of Windows 8 runs so deep that people are willing to risk any manner of computer calamity to get way from it. That would be bad news for Microsoft if they were fleeing to computers running Apple's (AAPL 1.27%) iOS or Google's (GOOG 0.74%) (GOOGL 0.55%) Chrome, but if they are willing to give Windows a shot at redemption then it could end in a victory for the company.
 
Does Windows 10 deliver?
While Microsoft used all the appropriate legal warnings to scare people away from the Windows 10 preview, I decided to brave it and upgrade a laptop that had been running Windows 8.1. The install was smooth and I have yet to experience any crashes or other issues that would be reasonable in such an early stage product. While early Windows 8 (which I also tested about nine months before its release while working as a vendor for the company) was hard to use, Windows 10 is not.
 
The OS adds some of the Windows 8 functionality to the classic Windows interface in a way that is organic and natural. Yes, there is still a learning curve inside some apps when not using a touchscreen, but basic functionality and using familiar programs including Office work well. The OS returns the Start Menu and smartly extends it with a version of the tiles that are key features on Windows 8 and the Windows Phone OS. The difference is that this time, their use is obvious and they enhance rather than detract from the experience.
 
This is what Windows 8 should have been.
 

The Windows 10 Start Menu is a mix of the familiar and the best of the new. Source: Microsoft. 

What does this mean for Microsoft?
A second poorly received OS could have driven Microsoft's core business customers elsewhere. That might have eroded or devastated a business that has brought in over $18 billion in revenue for each of the last three years. 

One million downloads of a very early version of the new OS shows that while it might not be as hip as Apple or Google, Microsoft still has a huge user base invested in its products. It might be too soon to dub Windows 10 a success, but there was no point in the Windows 8 life cycle in which it generated so much optimism.

Microsoft took a risk in making Windows 10 available so early: If initial feedback had been poor or few people were interested in the product, momentum for the new OS could have stalled. Now, Microsoft has an in-demand, much-improved OS on its hands. There's still a long way to go before it reaches the market, but the early results suggest it could be the hit Microsoft needs.