Application damaged or incomplete.

So I was working and suddenly one of the applications hang (rainbow wheel) so I did force quite and when I tried to restart the application I noticed it was erased from its folder. The app folder was totally empty. I quit all applications, run disk repair and restarted the computer. Now I can't open a lot of applications and I receiving the message that the application is damaged or incomplete. The icons are turned to error icons. Im talking about 20 appa are wiped out of my computer. I also received error message -10810 after trying to start one of the wiped out apps.

What happened? What can I do?