problems with airport and apps

[emmajanep]

Hi,

I have numerous problems with my macbook pro at the moment. This is really worrying me as I am in the middle of my Masters project and can not afford for my laptop to crash. I'm using operating system 10.5.7.

Last week my airport kept switching itself off, when it does this I am unable to turn it back on unless I restart the computer. I called the apple support team, they went through a list of things to fix it but it didn't work.

Now everytime I open up my color or motion applications I am asked for my serial number, my final cut studio is fully legal and registered so I don't know why it is doing this, it doesn't do it when I open Final cut pro.
Also firefox will no longer open, I even installed a new version but it didn't work.
I have tried deleting the serial file from the library and re-registering final cut but it hasn't worked, I have also tried repairing disk permissions.
I am very worried as I my laptop is very important to me right now and I really need to get the problem rectified, I would be very grateful if you could help me,

Thanks,
Emma