I've long wanted to be able to right-click any file in Windows and have “Edit with Emacs” among the options there. Upgrading my desktop computer after many years gave me the right motivation to finally implement little productivity improvements like this one. The following is a registry file that I've tested on Windows 7 and 10. It is hardly original—many others have posted similar things on Stack Exchange and elsewhere—but I'm documenting this version of it here really so I don't forget it myself.

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT*\shell]
[HKEY_CLASSES_ROOT*\shell\openwemacs]
@="&Edit with Emacs" 
"icon"="C:\\emacs-26.1\\bin\\emacsclientw.exe"
[HKEY_CLASSES_ROOT*\shell\openwemacs\command]
@="C:\\emacs-26.1\\bin\\emacsclientw.exe --alternate-editor=\"C:\\emacs-26.1\\bin\\runemacs.exe\" -n \"%L\""
[HKEY_CLASSES_ROOT\Directory\shell\openwemacs]
@="Edit &with Emacs"
"icon"="C:\\emacs-26.1\\bin\\emacsclientw.exe"
[HKEY_CLASSES_ROOT\Directory\shell\openwemacs\command]
@="C:\\emacs-26.1\\bin\\emacsclientw.exe --alternate-editor=\"C:\\emacs-26.1\\bin\\runemacs.exe\" -n \"%L\""

In the last month I assembled a new desktop computer for myself. This is my first significant upgrade in nine years, a timespan that my teenage self in the mid-nineties would have found unbelievable. At the time the upgrade cycle was something like three years long for anyone, even non-gamers, trying to keep up with typical software demands. In other words, the slowing of that cycle has allowed me to skip two major upgrades entirely, and I might even have kept going for a few more years except that my old video card was starting to fail with increasing frequency, and it wouldn't support DirectX 10. Although I'm not much of a gamer anymore, I had become aware of Planet Coaster, a sort of spiritual successor to the RollerCoaster Tycoon that consumed quite a lot of my time in the early 2000s, and obviously I had to play it.

AMD CPU after nine years, on the left, and the new motherboard, CPU cooler, RAM, and video card on the right.