Windows 7 doesn't show up I have 4GB Ram

[MrASSASSINo4ever]

I am using Windows 7 ultimate 64bit. Now the thing is I have 4gm ram (2x2) and it doesn't show in task manager that more than 2 is usable and in system information screen shows me I only have 2gb ram.

I have installed CPU-Z and there it shows me I have 4gb of ram.

So any help about this or I need to reinstall the system?

Rams are not from the same manufacturer but both are DDR3.
Mobo is G41T-R3

 

[xBlaz3kx]

Faulty stick? Test each stick if it works and also try changinh RAM slots.

 

[Kryptkeeper]

its a windows bug

 

[MrASSASSINo4ever]

its a windows bug

You sure?

 

[xBlaz3kx]

its a windows bug

You sure?

Its not. Tried changing the RAM slot and testing each stick?

 

[Kryptkeeper]

well im using windows 10 and it reckons my 2gb gpu has 6gb

 

[xBlaz3kx]

well im using windows 10 and it reckons my 2gb gpu has 6gb

Dont know how that's possible in Device manager or something because works fine with me.

 

[MrASSASSINo4ever]

its a windows bug

You sure?

Its not. Tried changing the RAM slot and testing each stick?

Turns out the RAM is not even working. Like I put it only and it wasn't working. PC starts but black screen. So biggest computer store sells broken stuff.. lol
Going to return it tomorrow. Thank you for your help.
Love this community!

But I wonder why it showed I had 4gb in CPU-Z...