Need Help!

I have PS CS5 and ever since I loaded it on my Mac at times I will lose the cursor.  I will have to move it off the page and try to get it to reappear sometimes this takes quite a while. Then it will pop back on and I start to work on pictures again using the tools and then it will disappear again.  This makes it very tough to work on pictures. Does anyone know what might be going on or what I could do to fix this problem?