Lost iphoto, system preferences and more

My 4 year old son has been playing with my Mac. It is Running Snow leopard.

System Preferences has a cross through it, so does my App Store. They say:
You can't open system preferences because it may be damaged or incomplete, when I click to open them.

It said the same for iphoto and google chrome

I started the computer in safe mode to take a look and verifiy that the HD was ok and it was.

I then restarted and now it still has the ghost buster sign over the system preferences and App store.

Now it also has a big ?, yes question mark symbol, where the iphoto and Chrome Applications were it the dock. I cannot find Chrome or Iphoto in my applications folder either.

And Microsoft Word has gone from the dock as well.

Any ideas?

This could only happen if you are using your Mac as an Admin User, and letting anyone else use your computer in an Admin Account is just silly. Turn on Guest Account if you want to give others a temp account.

Use Spotlight to find where he moved them to put them back into the right places (Applications) and all will be well. As long as he hasn't put them in the Trash and emptied the trash.