Keys are provided by your retailer (eg Steam, Amazon, GamersGate), please contact them for keys. Paradox do not directly distribute keys.
Are you sure you are entering it in the right game's field in MyGames? Between all expansions and editions, it can be quite confusing - for example an EU3:Complete code will only work in the exact EU3:Complete game's entry field, not in the one for EU3 or EU3 Chronicles. Similarly with almost all base games, expansions, and collections - generally each one has its own separate field for key entry.
If you can't get it to work, please submit a ticket at http://paradox.zendesk.com and include your key as well as what EXACT game(s) you have (a surprisingly large number of players forget this rather vital piece of information) and where you bought/downloaded it from.
You should also check and re-check that you are typing the key in 100% correctly, and are not confusing 0/O or I/l/1 for instance. Pasting the key in from your clipboard is best of course.
Transferring game keys after registration here
Registering a game here is effectively permanent. The game registration process is something of a kludge in the forum vBulletin software and Paradox have no ability to:
- de-register a game
- extract a game key from the forum registration
- move a registration to another forum ID
- merge forum IDs. Remember that having more than one ID here is against forum rules; if you forget your login details here contact firstname.lastname@example.org with as much detail as you can.
Second-hand games: as mentioned above Paradox have no way to transfer a game's registration to another ID here, so if you buy a game that the vendor has already registered here, there is no way to remedy that. Replacement keys will only be considered for new game purchases.
Europa Universalis III
Europa Universalis 3 has three separate editions that count as the "base game": EU3 itself, EU3:Complete (EU3+NA+IN) and EU3 Chronicles (EU3+NA+IN+HttT+DW), and ONLY those "base game" registrations count for access to the restricted EU3 forums such as Tech Support, Bug Reports, FAQ and MP. Any expansions you have separate to your base game should be registered too, apart from anything else it helps other posters comment more knowledgeably on any posts you make. And finally, a registration of DW or Chronicles is required for access to the EU3 MP Metaserver and to the Paradox Connect server (for EU3 Achievements).
There is a known issue with some of the older EU3:Complete codes that Steam issued (basically ones that start with COMS), there is a sticky thread in the EU3 main forum that tells you what to do about that. To add to the confusion, when Steam sell EU3 Chronicles they give out three codes instead of one: one each for EU3:Complete, HttT and DW so those codes will need to be entered separately in the respective game's entry field, none will work in the EU3 Chronicles field.
Supreme Ruler 2020
Try both the regular and the 2020 gold slot. If your key is less than 24 characters long, please add SUPR XXX at the start of the key, this should only be needed for the US boxed version of Supreme Ruler 2020.
MAC version of games
Paradox does not make the Mac version of any of their games except CK2; for those games you have to contact Virtual Programming www.vpltd.com for a forum key. This includes games bought from Apple's Mac App store. If you can't get this to work anyway, just submit a ticket here and we'll help you: http://paradox.zendesk.com
Edit: Post updated since we've reworked the registration page.
Castellon EDIT: To add info on the MAC versions.
AndrewT EDIT: added specific info about EU3, Macs, CK2