starting up problem

[j.ritzen@med.ruu.nl (Jaap Ritzen)]

Hello all mac users,

While making some changes in the systempreferences, the computer didn't 
react so I had to shut off the power and start over. But the computer 
didn't start up, the harddisk was ratteling like normal, the mouse came 
up, but then an ill looking monitor appeared on the screen with the 
warning codes 00000007  and 0000007E or something like that. I tried 
reconnecting the harddisk, waiting for a while, all the usual stuff. 
Then I tried to re-install the systemfiles but our systemcopies all 
weren't accepted by the computer. Even if they were put in before the 
computer was turned on. Do I have to keep some keys on the keyboard 
pressed or is it something else?

What's wrong and can somebody please tell me what to do?

thanx in advance,

Jaap Ritzen

j.ritzen@med.ruu.nl