Microsoft's (NASDAQ:MSFT) Windows 10 overhauls the operating system from the ground up.

The new OS is meant to be both an improvement from and an apology for the less-than-well-liked Windows 8. The company has already made it clear that the hated "Metro" interface (the screen that looks like a tablet's icon-laden interface) will no longer be the default launch screen. The company has also made it clear that the apparently much-loved Start menu will be back with enhanced functionality.

Windows 10 is a reset by a company which reached too far with its attempt to evolve its operating system. Windows 8 was optimized for a touch screen but a tad difficult to use with a traditional mouse and keyboard.

The new OS, which is available in work-in-progress demo form to people who sign up for the Windows Insider test program (of which I am a member), has the familiar feel of the OS pre-WIndows 8 with some intuitive bells and whistles. It's a leap forward (and probably what Windows 8 should have been) that the company is slowly revealing to Insiders and through its Windows blog.

The new OS holds many surprises. Here are a few learned from the company, media reports, and using the operating system as an Insider.

Spartan is the only new browser
Windows will ship with a new browser optimized for the operating system. Dubbed "Spartan," Microsoft has already publicly shown off some of the features of its replacement for its long-tenured Explorer brand. An early version of it can be seen by some Windows Insiders and the company explained the new browser in a blog post earlier this year:

Designed for Windows 10, Spartan provides a more interoperable, reliable, and discoverable experience with advanced features including the ability to annotate on web pages, a distraction-free reading experience, and integration of Cortana for finding and doing things online faster.

But, while Spartan will be the only browser pre-installed on the start screen, it will not be the only browser shipped with Windows 10. The company will still install Explorer on machines with the new OS, but it won't be a revised version. Instead, Microsoft will be offering Explorer 11 -- the current edition -- along with WIndows 10.

This is partly an acknowledgement that some legacy web sites will not be optimized for the new browser and partly a hedge in case people hate Spartan. 

A look at Spartan, Microsoft's new web browser. Source: Microsoft

Biometric authentications is coming
The new OS will offer Windows Hello, a system which allows instant access to devices through biometric authentication, the company announced on the Windows blog. Instead of having to remember and type in a password users, will be able to use their "face, iris or fingerprint" to unlock their devices -- "with technology that is significantly safer than traditional passwords," Windows boss Terry Myerson wrote.

Not all Windows 10-equipped machines will ship with this technology at launch. It will however be backwards compatible with any device which already has a fingerprint reader.

Source: YouTube

You can now write on Web pages
The most recent major release of Windows 10 for Insiders was really all about Spartan and its the first to show a feature of the new browser which allows users to write directly on web pages. The company uses the term "ink," and offers a small group of icons which look like a pen and paper that appear in the upper right corner of the browser window.

Click on this and the "inking menu" comes up which allows you to choose between a pen icon, a highlighter, an eraser, a text box, and a scissors/clipping tool. Once selected you can draw, makes notes, and highlight items on the page. You can also choose to type your thoughts which will appear in a box connected to a point you select by a thin line.

This feature is usable and intuitive. It's actually surprising that this is the first browser to have this sort of functionality native to it.

Windows 10 is a work in progress
While Windows 10 looks promising, it's still developing and people should (as Microsoft warns) install the demo version knowing that it's not necessarily a stable build. That said, as an Insider, it's hard to not find what the company has already released encouraging.

I did not dislike Windows 8 (I even worked on the launch of the news and finance apps as a vendor for the company during that period) but even as a fan I can see where there were valid criticisms. Windows 10 clearly answers those complaints while saving some of the best Windows 8 features and continuing to evolve the brand.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.