Windows 10: I can't activate my windows anymore after changing the whole PC

So today i changed my whole PC. I installed windows 10 PRO, connected to my account but the windows won't activated.

I already tried the troubleshooter and everything the Assistant told me to. Is there anything i can do ? Or it is over for me ?

:)

 

Windows 8.1 update changed the language, can't change back

Maybe, these will help... it seems it is a common enough problem.

Language packs are no longer available after you upgrade to Windows 8.1

And, sort of the same here --> Add a language or keyboard

Quote from above MS web page:

Spoiler Download and install language packs
You'll need to download the language pack if you want to make a language your Windows display language (that's the language you see most often in Windows and apps).

• Swipe in from the right edge of the screen, tap Settings, and then tap Change PC settings.
  (If you're using a mouse, point to the lower-right corner of the screen, move the mouse pointer up, click Settings, and then click Change PC settings.)
• Tap or click Time and language, and then tap or click Region and language.
• Tap or click a language that says Language pack available underneath, and then tap or click Options.
• Tap or click Download. The download process might take a while, depending on your PC and the size of the language pack.
  If you want to make this your display language, see the next section "Change your Windows display language".

Change your Windows display language
To change your Windows display language (that's the language you see most often in Windows and apps), first add a language, download and install the language pack, and then follow these steps.

• Swipe in from the right edge of the screen, tap Settings, and then tap Change PC settings.
  (If you're using a mouse, point to the lower-right corner of the screen, move the mouse pointer up, click Settings, and then click Change PC settings.)
• Tap or click Time and language, and then tap or click Region and language.
• Tap or click the language that you want to set as your display language.
• Tap or click Set as primary to move the language to the top of the list. If the language can become your Windows display language, you'll see Will be display language after next sign-in appear under the language.
• Sign out and then sign back in to finish.

And here is some more info --> Add Language Packs to Windows

 

windows activation—hardware changed siginficantly

From time to time on my thoroughbred PC, I get a Windows activation message that says my hardware changed siginificantly and I have to re-activate Windows. My hardware hasn't changed any more than a network card (went from a wireless g card to onboard lan to a wired network card), and the install is legit. Why is it doing this, and how can I stop it?

 

Windows 10 will not activate Error code 0x803F7001

thanks
I activated my Windows 10 from product key Windows 7