firefox won't launch

[peter lesterhuis]

Hi,
In order to visit a secured website I tried to import my certificate. I 
need to visit the website for my job. Until now I have to reboot into 
Windows and I am getting tired of having to do that. I was issued to 
download software from VerSign and then restart the browser. So I did. 
Now firefox doesn't start at all.
I removed ff en then reinstalled, but it still won't lauch. Konqueror 
does though.
Does anyone have a clue?
Peter