memory prob

the memory of my windows7 laptop does not increase even if i have deleted files. it remain the same after i had that trouble when i saved a file and got a message that getting low memory. i was not able to close the program because it all froze and i just shutdown the power. when i restarted the memory remain the same and keep getting lower each time i save a file. is there a way i could fix it? pls. help…thanks..