yup did the exact same thing, but my problem was the 2nd update to 8.1....
Hope MS WILL release a "full" installable ISO for 10 this time, and IF the 8.1 retail key won't work , send new 10 keys that will.
I tried the 10 TP & my 8.1 key was accepted & automatically activated since I used a Microsoft account.
How the 6/29 10 will act remains to be seen.
If you have a working legal OS I don't see why your installed key should not work.
If it would ask for a key it would be good to have it handy.
This vbs script will show your keys---
View attachment 62891
View attachment 62892
OK, look, what we, (me and this other guy) meant was we HAVE a RETAIL key, but in his case he couldn't get 8.1 to update his 8, and in my case I couldn't get 8.1 to do the update .1 or what ever it referred to as, so WE both had to go find an ISO to use as a "clean" installer. OKy, so since i don't have some MS "account" and I assume he didn't either, we got hold of a (in my case a torrent) ISO of 8.1. which btw isn't really "illegal" its just a TP anyway, cause it was only installable using some "public" install key, cause our "retail" w8 key wouldn't install the thing, ONLY after installing using the "public" install key could we use our "retail" key to "activate" the now limited by time, w8.1 install.
So we HAD our keys on hand, they just wouldn't work as a install key on this public installer. That's why I said MS should have put a good ISO out at that time so we that have a "retail" w8 key could install the thing. And its what I mean about this W10 upgrade, Give me a "retail" ISO and I'm sure my "retail" W8 key should work too. and since its a "free" upgrade for us, than send us a new W10 "retail" key to replace the "retail" W8 key I/we now have. (with the ISO) and were done......
Ironically, I have never even used the installer since the first time anyway, once my system is up and running, and all updates done, I always make a new Image anyway, I use 3 different imaging programs for that, as backups to backup, and when ever I need to "recover" I just use the USB boot stick and recover the image (from MS file history imaging), The other backups are just that "other backups" in case. I've found the built in imaging program works real good, and have confidence in it now after having used it. The main reason for the full installer is if I got another computer and wanted to install a clean copy to start off with of 10 with the "retail" key.