I've had this computer with Windows 10 for about 3 weeks. I really want to go back to Windows 7

[ucrdem]

8. If you have other PCs with Win 7 you probably have at least one product key you can use

to activate a Windows 7 installation on your new PC. If you don't have an old installation disk you can download the software from MS here:

https://www.microsoft.com/en-us/software-download/windows7

Once you download it onto an empty thumbdrive you can install it on your new PC, either on top of 10 or as a dual boot, by sticking the thumbdrive in a slot, turning on the PC, and carefully following the prompts. Back up your data first and cross your fingers. You might have to get into the BIOS commands by pushing f8 or f10 right after turning it on to get it to boot from the thumbdrive, but maybe not.

Alternatively you can keep 10 and add Classic Shell which is free and includes a 7-style start button which is very customizable and basically lets you use your PC as if you had Windows 7: http://www.classicshell.net/