There is another possibility.
Possibly something mischevious has changed the settings on your computer.
Are you sure the programs are gone, or just hidden?
If the latter, have a look here.
First. Open , in windows explorer, Tools - Folder Options - View. Make sure you have the option "Show hidden files..etc, ticked. -- Apply.
After this, if you can now see the missing files, right click a couple and check properties, untick the option "Hidden".
You may need a reboot after the first step.
All failing, start a new account using the Global adminstartor. If you are not familiar with that, there is a tutorial on this site. Try the above again.