Many of them are now eagerly awaiting Windows 8, because they have held out for a long time and have great hopes for Windows 8. They really don't want to jump into the arms of Google and Apple. They will if they have to, but they are waiting for Microsoft's final olive branch before deciding.

If Windows 8 gets rave reviews, these people will be relieved and may go all-in with Windows 8, from PC to phone to perhaps a tablet.

But if any or all parts of Windows 8 -- PC, tablet or phone -- get shaky reviews or the feedback from the early users is so-so or worse, the risk to Microsoft is tremendous.

You might say, "Well, isn't this self-evident? Wasn't this also the case with Windows 7?"

No! When Windows 7 launched, the PC alternative was Mac, and Microsoft continued to lose (a little bit of) market share even though Windows 7 was an excellent product. There was no Google in the PC space, no Android to any meaningful degree, no iOS, and no tablet market. The phone competition came primarily from Research In Motion ( RIMM), Nokia and Palm -- companies that are now at or near 0% market share.

This time, Microsoft stands to lose it all if there is more than the slightest unhappiness with Windows 8. This was never the risk when it launched Windows 7.

So what are the pain points that could lead to bad reviews from journalists or negative customer feedback? Let's take the three main versions of Windows 8 in turn:

1. Windows 8 for x86:

With the consumer market already flipping to various classes of alternative operating systems or other kinds of "post-PC" devices, much of this market is enterprise. Enterprise users may not take kindly to the new "Metro" tiles-interface in Windows 8. Yes, I know you can click away from it and get into something that looks sort of like the old Windows 7, but this could still annoy and confuse a lot of people.

Some years ago, Microsoft basically tried to cram the desktop Windows XP into mobile and tablet devices, and users hated it. This time, the company has tried to do the opposite: Take Microsoft's excellent cell-phone interface and blow it up to fit PCs, which people use to do real work, usually involving multitasking. This has a major risk of becoming an epic disaster.

If you liked this article you might like

Your Complete Guide to Living Like Billionaire Warren Buffett

Why Amazon's Reported Smart Glasses Might Be Just a Niche Product -- For Now

How To Get a Promotion Using Legendary Former GE Head Jack Welch's Strategies

Microsoft Has Been Reborn Under CEO Satya Nadella