I have a mobile Home it's old I had the power shut off since I'm not living in there but now I'm letting a friend stay in there so I and him have started to replace all of the outlets in the house now that most of them have been replaced I have lost power to the dinning room lights and 2 outlets that ran off the switch. And one in the living room that's problem 1

Problem 2 is that I have a GFI breaker and I want to replace it can I use a standard 20amp breaker inplace of the 20amp GFI. The GFI breaker will not stay on I believe that the breaker is bad.

Problem 3 Is that I seem to keep blowing a breaker I replaced it with a new breaker and so far It has only triped once but the breaker I replaced did'nt even belong to the box.

Problem 2 is that I have a GFI breaker and I want to replace it can I use a standard 20amp breaker inplace of the 20amp GFI. The GFI breaker will not stay on I believe that the breaker is bad.
Chances are the breaker is doing its job, there is a short somewhere.

If you had a GFI breaker chances are you need a GFI breaker.

As Mower said, it is doing it's job. You either have a short circuit or a ground fault. More likely a ground fault.

Are you replacing everything EXACTLY as it was?

Yes I have replaced everything exactly as it was, I had put a standard 20 amp breaker inplace of the GFI breaker and everything ran OK but the dinningroom. Problem 1, What makes me suggest that the breaker is bad is that when you move the breaker on and off the switch seems weak. Not a loud clicking noise. Would it hurt anything if I just used a standard breaker in place of the GFI.

would it hurt anything if I just used a standard breaker in place of the GFI.YES. As we have said, the GFI breaker is likely there for a reason.
What does this breaker feed exactly? Receptacles in the kitchen? Bath? Outside?

You can have the GFI breaker, or GFI Recepticle(s).
Remove load(wire) from breaker, if it doesn't reset, it is bad.
The solution to the other problems will require removing recepticles, switches, and tracing out.