Sounds like a mismatch between the clips and the Sequence settings, for instance putting a 1080 HD clip into an NTSC DV sequence (SD) or vice-versa.
You can drag a clip onto the New Item icon (next to Trash Can) in the Premiere project window and this will create a New Sequence to match the clip. If you later add clips to that Sequence that don't fit, you can right-click (Mac may be different) and select "Scale to Fit".
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Awesome Jeff that did it. you dont know how much time you just saved me. YES!
A way to streamline the process of scaling down your clips is to go into Preference - General - "default scale to frame size". Make sure that box has a checkmark in it. This won't fix the clips that you already have in the project… to have this work you will need to re-import the clips after checking the box. I do this when I'm bringing in 4k clips that I want to fit in a 1080p timeline.