The tool gAttach! from this old article Make Gmail your Default Desktop Email Client (Windows)
Make Gmail your Default Desktop Email Client (Windows)
can no longer be downloaded. What happened to gAttach.com or whatever website it was supposed to be on?
as you noted yourself, the article is quite old. gAttach! is now Affixa. I wrote an update to my article, which also features a few other ways to make GMail your default email client. Check it out here: 4 Ways To Set Gmail As Your Default Email In Your Browser