The Windows version you have needs to be 64bit in order for your sustem to recognize the whole amount of memory
Also, depending on which version of Windows you have, it has a limit of maximum memory
Version Limit on X86 Limit on X64
Windows 7 Ultimate 4 GB 192 GB
Windows 7 Enterprise 4 GB 192 GB
Windows 7 Professional 4 GB 192 GB
Windows 7 Home Premium 4 GB 16 GB
Windows 7 Home Basic 4 GB 8 GB
Windows 7 Starter 2 GB N/A
Windows 8 Enterprise 4 GB 512 GB
Windows 8 Professional 4 GB 512 GB
Windows 8 4 GB 128 GB
Thanks for reply guys.
HAVE DISCOVERED PROBLEM ,IN MY ADOBE FILE IT CONTAINED 32 and 64 bit folders,
And even though I was using the 64 bit photoshop file the 32 seemed to be overriding
It ,so I deleted the 32 files and now everything's fine. I now have 10gig allocated.
Don't no why it does this as my Windows is running on 64 bit.
I think this may be the problem a lot of people may be having as I searched online for the answer.
THANKS