I accidentally deleted the Software Update from System Preferences off of my MacBook. Help!

I accidentally deleted the Software Update from System Preferences off of my MacBook (late 2009 model). I have tried to look for the files caches in my library and in finder. No luck. It seems to be slowing down my computer a significant amount, as well (since there are no updates).

However, under the apple button in the top left corner, the System Update is still there, so I know that it is still somewhere on the computer. Yet, it always says no udates available, and I know that there should be some.

Is there anyway to get the Software Updates back into System Preferences? If so, after that is done, what are some ways to overall clean up my computer (other than resetting safari and deleting trash, etc.).

If not, would completely wiping the compter and purchasing/installing Mountian Lion or Snow Leopard fix the problem? Or maybe a factory reset?

Help please!