If you want to use win7 system, you should also buy Air. If you install win7, it will be more stuck, and win7 takes up more memory. If you have to install win 8 system, I suggest it will be faster. If win7 system is installed with Air, it must be installed with USB flash drive. First, you need to download a mirror file of win system on the Internet, make a USB flash drive startup item, and start it with USB. Specific steps can be searched online, and there are plenty online. But personally, it is not recommended to install win system. After installing win system, it is not so easy to install the original system.