Matlab 5.1 cant run in Windows 7

Hi,
I am a Communication Engineering student. I need to simulate different types of wave and signals. Everyone knows that MATLAB is the best software for that purpose. I had bought MATLAB 5.1 few years ago. Now after releasing windows 7 I can’t run MATLAB there. It says a serious error has occurred and MATLAB have to restart.
What is the problem there?
How can I get rid of it?
