Windows 7 Not Using 4GB Of RAM - Only 1.76 Usable

I have 6144mb of ram on my Compaq Presario CQ62 402AU. So I have the 2GB Hp stick which came with the laptop (2GB DDR3 1066MHz) and I have a 4GB stick from G-Skill). So there should be 5.76GB usable, but I only have 1.74GB usable. This is what is it when I only had the 2GB. The Bios says there is 6144GB in there. Windows says there 6.0GB in there also.

So what I have tried:
- Running Mem Tests (HP one which came with my laptop and Memtestx86)
- Taking out the ram and putting them in there sorts again
- Taking out the ram, running a pencil eraser over the connecters and then putting them back in
- Doing testing so Only 1 is in and try that in both slots for both sticks of ram
- Swapping the ram positions
- Making sure that Max ram is not selected in Msconfig

So basic System info you may want to know (Most of my profile info is there of my computer) Windows 7 Home Premium 64-Bit SP1 Installed Memory (Ram) (This is from the basic system info page) 6.00GB (1.74GB Usable). The odd thing is that it worked fine for a while. Today I went to school with the 5.76GB and I come back home 8 hours later, the computer has only been on lock for this time and there is only 1.76GB usable.