I wanted to install Windows 7 on an old/retro PC build. for nostalgic reasons. Yes, I know the security risks, I won't put any important stuff on the PC, just want to get the feel of Windows 7 again. It has special place in my heart :)
Thanks in advance :)
That won't be a legitimate install if you don't have the correct Windows 7 product key for it!
1. Windows 7 does not come for free; you have to buy it.
Microsoft no longer sells it and I can not recommend anywhere that is safe to buy 7 from.
2. You would have also had to have made sure that your computer manufacturer supported Windows 7 and supplied Windows 7 drivers on the exact model number you wanted to install 7 on for it to install and work correctly.
Warning:
You do not buy a Product Key by itself, as they are normally stolen/pirated, Volume Licenses which are not for private use, or MSDN keys which are not to be sold by the original subscription holder.
Make sure that you buy the complete sealed package (DVD, license)
https://www.microsoft.com/en-us/howtotell/Shop.aspx
Read Section: Beware of Product Keys sold separately.