hi guys,
I read that if you buy an Xbox One version of FH3 you can play it on PC too. But do i need to activate the Xbox One Code before i can play it on PC? Or is the Key itself the same for Xbox One and PC? The problem is that i cant update Windows 10 (blackscreen error, cant fix it…) and without the anniversary update i cant Preorder FH3 in store, because the shop dont find FH3.
Or do i need to wait for the retail version?
http://forums.forza.net/turn10_postsm543812_Forza-Horizon-3---Game-Guide---FAQ.aspx#post_543812
As stated you NEED the Anniversary Update for tha Game.
You should be able to buy it on PC without needing an Xbox. It’s a vice versa thing, so should you ever get an Xbox One, Horizon 3 will be playable on it as well as PC.
There won’t be a retail version for PC. There’s not going to be a disc - only digital for PC, so you’re going to need the Anniversary update. If you’re having problems updating then you may have to reinstall Windows from a recovery disc.
Ty guys!
Well i gone the extra mile and just reinstalled win10 (clean install) and now it works, luckily i have all important apps on my external hdd.
EDIT: It appears you did this whilst I read other threads. Serves me right for not refreshing the page. 
As others have stated - you need the Anniversary update to play FH3. Without it you’re not even getting to the starting grid. If you’re getting a black screen then a clean reinstall of Win10 is your fix.
For your other points:
I believe it’s the same code for both and it’s tied to your MS/Xbox Live account (you also need the free one of these). I don’t have my code yet so I can’t say for certain. When you redeem the code it allows you to download it on both PC and Xbox if you own both. If you only own one system you simply download on that one.
There is no retail/disc version for PC. When you get around to ordering make sure you get digital. 