Quote: " If I use a key with one computer, does the activation of GameGuru carry over if I sign into my Steam account from one of my other computers?"
Every Steam app I have plays on any PC I have Steam installed on. This appeared to work with GG as well, however, on my 2nd PC (so far), GG will launch, but it will get stuck on that opening screen that tells you about videos, etc. and I can't get past that now. I'm still working on resolving that issue. Earlier I had discovered I could stream GG from my laptop to the 2nd PC which is my actual game machine (MAME cab) (just like sharing a desktop) , so, of course I tried it while simultaneously downloading and installing GG on that machine. Therein may lie my problem. I am also running a ton of updates.
MAME Cab PC: i7 4770@3.4Ghz (passmark 9945), 12GB RAM, Win 8.1/64, GeForce GTX645 (passmark 1898); Shiny new laptop: i7 4800MQ@2.7Ghz (passmark 8586), 16GB RAM, Win 8.1/64, GeForce GTX870M (passmark 3598); Old laptop: i5@2.3Ghz, 8GB RAM, Win 7/64, Intel 3000 graphics