You need to check in the Programs list. Go to Start > Control Panel > Programs and Features > Uninstall a program. The applications should be listed there. If they're not, it means they've been uninstalled because of an error, mistake, or because of another's program uninstall.
In case the apps are there, go to C:\Program Files and search them in that location. Most likely, only the shortcuts to the main executables have been deleted. You can restore them by right clicking and selecting Send to > Desktop (Create shortcut).