OS X :: Dock Won't Appear & Expose Doesn't Work?

in the past week or so this minor problem began to occur. expose suddenly doesn't work, my hidden dock won't appear when I move my mouse to the bottom of the screen, when I move my mouse over my bookmarks in Safari, they don't "highlight" like usual, my mouse pointer arrow doesn't change to the "hand" when moving over links, etc. This is very strange, when I click Safari at the top of my screen I actually have to hold down the left click to scroll down to "preferences" or "quit" or whatever. i can't single click and just drag down. i have to actually click and hold.