Windows sees 16gb of ram but can only use 7,97?

I just build my new pc and i installed 16 Gb of Ram(CORSAIR VENGEANCE), when i installed windows is sat it to activate later. when i had installed windows and were booted intro windows it used all 16Gb, and all was fine, but then i had to activate windows and at the time my internet was down so it didn't work. so windows said that my windows were a pirate copy, butt any ways i got my windows activate later that day butt windows says that 16GB of ram is detected butt only 7,97 can be used. PLz Help!.

Welcome to Windows Seven Forums.

Can you please confirm how and where you bought your copy of Windows?

Which media are you using - DVD or USB?

my copy is legit i used a cd to install it...

And i bought my copy on a Norwegian online store called komplett.no

8GB shows up in CPU-z

Please type Resource Monitor into Start Search box, rightclick result to run as Admin, click on Memory tab and post back a screenshot of the chart showing RAM apportionment.

Test your RAM - Test with Memtest86+.
There are specific steps to test both RAM and slots.

Swap your RAM sticks, check for debris in slots. Run Sticks individually to check detection, then add another stick to check again.

Remember to touch metal on or inside the case before touching any chips or components, to avoid ruinous static discharge.