Windows 10: Windows 10 activation after upgrading hardware, don't have product key.

I recently upgrading some parts in my self built PC. I originally built it in 2013 I think, and I purchased an OEM windows back then. Since, I've lost the box that had the product key and also did the online upgrade to Windows 10. When I upgraded the parts I did not get my key off my PC before upgrading. Will I be able to activate windows now without purchasing a new copy? I kinda can't afford $140 lol.

:)

 

DOWNLOAD WINDOWS 10 NOW - Upgrade and ISO direct from microsoft

this search might help you https://www.google.com.au/webhp?sou...o+to+get+it+activated+windows+10+blocked+keys

From http://windows.microsoft.com/en-us/windows-10/why-activate-windows-10

If you upgraded to Windows 10 for free and ended up in a non-activated state, try following these steps:

• Go to Start
  
  , then select Settings > Update & security > Activation.
• Select Go to Store, and check to see if a valid license is available for your device. If a license isn't available, you'll need to buy Windows from the Store.
  
  Note
  • This only applies if you haven't made changes to the hardware for your device.

or you could hack it with a crack but please note this is always risky and you don't know what's in the hack

 

Windows 10 will not activate Error code 0x803F7001

thanks
I activated my Windows 10 from product key Windows 7

 

DOWNLOAD WINDOWS 10 NOW - Upgrade and ISO direct from microsoft

Click to expand... Yeah I went to that site, why do I need to buy a key?
I won't buy a key, stupid.

I'll revert back to windows 7 then.

When I still was on windows 7, about a year ago I added 4GB extra ram which is a total of 8GB now,
is that causing the problem?