please help! programs won't launch, and new programs can't be installed

[Mia]

HI,
I seem to have a major problem with my Ibook G4 10.3.9.
Ealier today my mac fell to the floor from a coffee table. But afterwards it seemed to work fine - I played music from Itunes and surfed the internet with Safari no problem. But then Ical wouldn't launch and things froze, and I ended up having to shut down the mac with several programs open incl. Safari. After turning it back on more than half of my programs (Safari, Quicktime, Iphoto, Acquisition, Limewire, Mail, Addressbook, Ical) refuses to launch! Itunes seems to work fine, and I can access the internet with Firefox or Internet Explorer - but not Safari. Some programs eventually opens the upper bar of the program and seems to be open, but is otherwise invisible. In Safari the beachball-like symbol just keeps turning before suddenly unexpectedly quitting. Also: I can't install any new programs! After download the install popup appears - but with all text missing! And I can't get any further.
If anyone has any suggestion to what kind of problem I may be facing here - I would greatly appreciate it. PLEASE HELP!, thanx very much, MIA.

[eric2006]

Did you try the repair options in Disk utility? (Disk utility is in the Utilities folder, which is in the Applications folder)

[ra3ndy]

There are good odds that you've physically damaged your hard drive (especially if the drive was being accessed when it was dropped)

I recommend getting all of your personal data backed up ASAP before you try fixing anything. This is important! The more you tamper with a damaged drive, the worse it gets.