Stop and Play:controlling movie clip?

Flash Gurus, you are the only ones that can help me with this!

Is there any way I can do these things:

I have a welcome screen where players can choose easy or hard mode. I want each button to load the correct .swf when pressed. How can I do that if I want each .swf to load in a new frame?

Also, if I want to have a **Stop **and **Play **button that controls a short animation, what AS do I need for that?

You really will do me a huge favour if you manage to crack :+) these little nuts!

Any ideas?