Dave, what is wrong with your garage door? Replacing panels and such is relatively easy. If you have any problems with the springs, let a pro handle it. they are under extreme tension and can cause serious injury if you do not know what you are doing.
I've written a whole series of articles on basic garage topics...doors, sensors, cables etc.
Take a look and see if they answer your ? ...if not ask more specific here and we should be able to help you out.
Dave, garage doors can be a scary thing. I agree with Dan, if you're talking about anything involving springs, call a pro.
Dave, at least go and find a pro to speak with before taking this on. I don;t want to see future posts sent from your hospital bed. Good Luck!
I am a very technical guy, but recently i tried to fix my own garage door and man was i ever sorry. This is a task better left to a pro.
Especially if you are dealing with the springs... a wrong move and you can do some serious damage or critically injure yourself.
I agree with all of you. Springs especially are a dangerous business. You should call a pro to fix that.