MAC Issue

I have a MAC because my school gave it to me so this was not something I chose to do. But here I am, finding myself using it more and more as my PC sits off to the side. My MAC is MUCH lighter and quicker, and so there you have. BUT I am having an issue. For the past two weeks, there are times I turn it on and my entire desktop is shifted to the right, so much that I can't even see the icons on the right. Then it will begin to flash repeatedly. If I take out the battery and let it sit for a bit, it fixes itself - but I want to know if you are a MAC user, do you have any insight??