I do not share memory with a video card. I have 4 MG of DDR2 and an AMD64X2 5600 CPU and a M4A78 Asus board.
A gaget (meter) of Win 7 shows I am using 25% of RAM while the CPU is at rest.
Is this normal and if so why is it?
Yes, this is normal.
Windows Vista/7 actively stores some of your most commonly used applications in memory to speed up starting them.
If the memory is required by another program, it is immediately freed and reallocated.