How much memory does the machine have?
It sounds like 1 gig or so! You need to get more - like 4 gig of it.. Go to
RAM Memory Upgrade: Dell, Mac, Apple, HP, Compaq. USB drives, flash cards, SSD at Crucial.com and do the free scan to find out how much you have and what you can load in it.. And order it right there if you want. I have used them for years - Please note I did learn about memory compatibility. I bought one chip and loaded it and did not gain anything as the new memory canceled out the old.. so simplest way is replace it all..
Good Luck!