These include Microsoft Windows, Chrome OS and Linux, and each although may come across as being aesthetically different upon first glance, they do offer different functionality and better yet handle software differently.
Software that works well on your old operating system might be compatible with your new OS and in worse cases software for your new OS might not even be available. For example, Microsoft office will work its best when plugged in to a Windows OS computer, but will function differently when used on a Linux or MAC powered computer.