Windows 7 Assistance and advice requested

I have the standard 4gb of ram in my Win 7 pro media center 64 bit edition. Custom build. Crucial 64mb ssd updated with a 1.5 TB, and a 1 TB HDDs. My system is continuously using 93-97% ram memory according to Windows. I have tried turning off everything I can to lower the usage, stopping programs, bare essentials in startup, stopping processes etc. and nothing helps. I have scanned for Malware in safe mode and in normal ops. Scanned for viruses also. I even designated a special partition to use as a cache, and created a ram drive. Nothing helps. MSI motherboard. Not overclocked. What is wrong, what am I overlooking? I cannot afford more ram memory at this time.