Question mark over certain applications

question mark over an item in the dock means that the original item can not be found because it was either moved or deleted. first check you main Applications folder. that's where those things should be by default. if they are not there they may have been moved, do a spotlight search for them. try it from all user accounts you have on the mac as sometimes people move the apps to the desktop or a place like that. also check the Trash on all accounts. if the apps are nowhere to be found you can reinstall them from the leopard install DVD using pacifist
http://www.charlessoft.com/

you'll have to install 10.5.7 combo update afterwards to bring those apps to their latest versions.

first, did you do a thorough search for the apps on the computer? only go via Pacifist if they are truly gone.

and no, you don't drag and drop in pacifist. start pacifist and load the install disk in pacifist. enter the name of the application in question (like Photobooth.app) in pacifist's search field. it will find it for you on the install disk. if there are many results select PhotoBooth.app. click "install" and follow the instructions. repeat for every missing app.

once done, download 10.5.7 combo update and install it.
http://www.apple.com/downloads/macosx/apple/macosx_updates/macosx1057comboupdate .html