帮我解释一下，这是啥意思。

Preloaded Operating System - Type of operating software pre-installed on the computer. This would usually be a version of Microsoft Windows? Upgrades to Pro versions of Windows (for added security and networking features) are sometimes available at time of purchase.

买电脑时有了这个软件，是否就不用再买新的软件了吧？有朋友讲这只是一个试用版。