Microsoft always aimed to stop Joe and Grandma from installing Windows without paying for it, but otherwise didn't make it too difficult to install and use Windows. Just like Adobe, Autodesk and such.
With 98SE you simply needed to learn the key (VGF6G-7JJVD-...) to be able to make unlimited installations. There was no need to burn a disk, even : format a hard drive, put bare DOS on it ("format d: /s" does it), copy the \WIN98 or such folder.. then put the hard drive in the other computer, boot, change directory, run the setup. To make it faster, do the same but have your DOS use SMARTDRV.EXE.
So, the installation is reasonably fast, you paid nothing/didn't deal with licenses, and you have the Windows CD-ROM's content handy when the system prompts for it (adding/removing components, drivers etc.)
With Windows 8.0/8.1, as far as I know for using a computer with no legit license, Windows nags you about every 24 hours by displaying a fullscreen Metro-esque screen. Says something about activation or license. You wait five seconds for a link to appear, you click on it. Then you escape the thing the same way you try to escape Metro, by mashing Alt-tab/Windows key/Win+D until you're back to your application.
Microsoft by the way had a program to "redeem" warez Windows on old PC by paying a fee I think, and has another one that gives away legit Windows to non-profits (evil plan so they don't install linux instead, but if we give them the benefit of the doubt it's a commendable thing.)