Didn’t knew that, but only if they also sold windows pc? Like, if a company would only sold blank PCs without any offering associated to MS they wouldn’t need to pay MS anything.

That was the what the trial about. If you wanted to contract with MS you had to pay for a license on every box shipped. Dell, Compaq, Gateway, HP, IBM, Acer, and others had to sign the contract or ship only alternate OS’s If one sold a computer with OS/2 they also paid for a windows license.