Microsoft rolled out Windows 10 on Wednesday, making the new operating system available to the vast majority of the PC and Windows tablet universe. For those who were frustrated by Windows 8, this should be a welcome update. So how do you jump on board? First things first: You should figure out if you can upgrade and how much it’s going to cost. Most Windows-based PCs out there should be able to upgrade, but not all of their owners will be able to do so for free.