Users of Windows 7 and 8 can upgrade to version 10 of the operating system for free from the end of July. Not so for those still running the Microsoft Vista or XP systems.
Those people will have to buy a new Windows 10 licence, unless, that is, they're willing to make do with a beta version of the system for the foreseeable future and become an Insider.
This test version is free and will remain so after the final version comes available on July 29.
But users will have to accept that some bugs and glitches will be present in the system, with regular notifications sent to Microsoft when they crop up.
Because it's never a final version, the successive incarnations of the beta option will be less stable than the finished product.
But there are ways to avoid the worst risks.
For example, when signing up, join the Slow Ring.
That's different from the Fast Ring, where users get changes quickly, which means they get the newest stuff first, but also have to cope as bugs are worked out.
Those in the Slow Ring get the versions that have already been worked over by the early adopters, meaning most of the kinks should, hopefully, be worked out by the time they get an upgrade.
German computing magazines say another good option is to buy Windows 7 now and get a free upgrade to the gold-plated version of Windows 10 later.
Windows 7 can often be found on sale at a steep discount.