Some PCs are now sold without an operating system. However, installing Windows 10 on them is easy if you follow this complete tutorial. You don't have to be an expert in this regard. The same operations will be valid in case of reinstalling the operating system.
If you buy Windows 10 online or if your laptop does not have a DVD drive, the best alternative to installing this operating system is to use a USB flash drive. However, installing Windows 10 with a DVD-Rom follows the same principle. You just have to follow the different steps we list in this article.