PLEASE resolve my slow sheet issues? When I enter data it's like I have slow internet or something BUT I don't. I have a wired desktop with Gigabit data speeds. However, every entry is so slow! What's up?!

I heard that sheets with too many cuts and pastes might be the issue. How to I refresh this or something? I can't last much longer operating like this! I'm about to find a microsoft or apple solution if you don't do something quick.