Not accessing all my memory

[DOF1202]

I have the Linux-Mandrake 6.0 (Red Hat Linux 6.0 with enhancements) install 
along with Windows 98.

I have 128Mb of ram and a 128 Mb swap file. But the system says that I have 
13.9Mb of ram and 131 Mb of Swap file. 

The Hard disk is continously thrashing away as I bring up programs etc. And 
the OS is pretty slow. I believe that Linux is only using 13Mb or my system 
RAM, How do I get it to recognise the rest of my ram?

Thanks in advance for any help.
Ed Santiago