Thanks to Microsoft's free upgrade offer, computer users are moving to Windows 10 in droves. Microsoft says 14 million users upgraded in the first 24 hours, and it's aiming for a billion in two to three years.
For some people, Windows 10 is a smooth upgrade and great experience, but other users are having trouble. For instance, earlier this week some users got caught up in an endless reboot thanks to an update that conflicted with certain graphics card drivers. For other users, it's basic things like the sound or other simple hardware not working correctly.
In most cases, the problem is incompatible hardware drivers. Drivers are basically small programs that make sure Windows and other software can use the computer's hardware correctly. Your computer has a driver for your sound card, webcam, mouse, hard drive and everything else.
Windows has a lot of generic drivers built in that work with a wide range of hardware, but some hardware still needs very specific drivers to work right. And not every driver has been updated to work with Windows 10.
This is especially a problem on laptops, which tend to need more specialized drivers than desktops do. That's why one former computer maker is recommending its users NOT upgrade to Windows 10 right now.