Win7 64 bit showing 2.75 GB ram instead of 4 GB

[rohitshakti]

I am using Win7 Ultimate 64 bit OS. I have 4 GB Ram (XMS3 Corsair). Till yesterday my PC was showing 3.5 GB ram used but now it is showing 2.75 GB of ram in use. I had used the ready boost for my Kingston 4 GB pen drive yesterday and I think it had happened only after that.

Pls tell me how to correct this error.

 

[ethel]

What graphics card are you using?

 

[jaquith]

Try Memory Remapping -> Enabled ; on 64-bit OSes. Next if you have a single 4GB stick see the manual for which DIMM slot to use for a single stick; yes I noticed DIMM slot 2 which for 'most' Dual Channel MOBO is correct.

I assume the missing is in the form of Hardware Reserved:

edit: Check MSCONFIG is as pictured: