How to upgrade to Windows 10.
New Link: https://www.microsoft.com/en-us/software-download/windows10
LINK (OLD): https://insider.windows.com/
Windows 10 FAQ: http://www.microsoft.com/en-us/windows/windows-10-faq
NOTE: You need to have SP1 installed on Windows 7 in order to upgrade to Windows 10 using the Windows Update method shown in this video. If you are upgrading from Windows 8.1 some apps may not be supported yet on Windows 10.
Processor : 1GHz or faster with support for PAE, NX, and SSE2
RAM : 1GB (32-bit) or 2GB (64-bit)
Hard disk space : 16GB
Graphics card : Microsoft DirectX 9 graphics device with WDDM driver
Product key: 6P99N-YF42M-TPGBG-9VMJP-YKHCF
1/2/2017 UPDATE: As of writing this comment, you can still get Windows 10 for free as of early 2017. I made a tutorial back in July 2016 showing how to upgrade from Windows 7 and Windows 8 to Windows 10 after the "official" July 2016 deadline, and that tutorial still stands.
This is a tutorial of how to upgrade to Windows 10. You can upgrade to Windows 10 from Windows XP, Windows Vista, Windows 7 and Windows 8.1. However, only WIndows 7 and Windows 8 are eligible for the free upgrade until July 2016. Shown in this video are no cracks, hacks or key-gens. This comes directly from Microsoft so it is safe (in terms of no malicious software).
This tutorial applies for users of Windows 7 or Windows 8 looking to upgrade to Windows 10. Windows 10 comes in different versions (Home, Professional, Enterprise) and depending on which version of Windows 7 you are using (Starter, Basic, Home Premium, Professional or Enterprise) or Windows 8 (Home or Pro) this will affect which version of Windows 10 you install. Make sure you select the right version of Windows 10 along with the correct 32-bit or 64-bit denotation. Windows 10 can be installed using an automated process through Microsoft or the ISO file can also be downloaded and placed onto a USB/CD/DVD and installed on a computer that way (if preferred). The latter method is best when installing Windows 10 on a different computer.
This tutorial will apply for computers, laptops, desktops,and tablets running the Windows 10 operating system (Home, Professional, Enterprise, Education) from all supported hardware manufactures, like Dell, HP, Acer, Asus, Toshiba,Lenovo, and Samsung).