Files gone?

[mac15]

I just installed my new Alcatel Speedtouch USB modem and I got a kernal panic, I rebooted looked in my HD and half my HD was gone, I was stunned, I lost apps, luckily no music, but could anybody explain what went wrong?

[Sun Baked]

Did you go through the "fsck -y" routine, and then under OS 9 run Disk First Aid and rebuild the desktop.

And i already hope you know that fsck -y and DFA should be run until all the problems they can fix are fixed.