Dock Problem It won't open at all even after restart!

Randomly while I was doing some website work my dock disappeared and will not reappear even after I restarted my machine. I have checked all the simple prefs and everything but it will not work. If I shrink a single window it slides to the bottom as though the dock is there but when I try to reopen that window or a new app the dock will not reappear! If it matter my machine has also slowed signicantly suddenly. I am running leopard on a macbook pro if anyone can help.