My iTunes on my iMac is in an endless loop of starting on it's own and then crashing

How do I stop this endless loop of iTunes starting on it's own and then crashing only to begin over and over again? It has made using my iMac useless as the crash report window always covers whatever other window I have open. Since it's in an endless loop, closing the window will do no good as the next crash will cause the window again to cover all work! I'm using a mid 2007 iMac with Lion and the latest version of iTunes. I'm starting to feel like my mac is Microsoft Windows machine with the constant crashing! Thank goodness it's only the iTunes program that's crashing and not the computer!