I am a Beginner to Programming,

I Have Just Started School to be a Computer Programmer,But My Experience has So Far Been only Slight Upgrades,and adding Some Hardware with the Needed Software.I had a Computer Programmer Upgrade My Gateway 500 Essential to be able to Support a 60GBHard Drive From a 7.5GB Hard Drive.I was able to Watch Him Some and Learned a Little Then.Somehow the PC is Resetting itself to only Handle the 7.5GB,only able to accept 3-4GB How Do I Fix this Myself So I can Keep It On the 60GB Drive,I Cannot Taketo the Programmer Every Week For a Tune Up.