Vegas Pro 9.0 help

what is the footage format?

and also , what kind of camera are you using,
what are your computer specs ( RAM , processor, Graphics)?

Select the clip, press shift+b, go back and play, profit

um im on quick so ill check the specs later but im shootin in 1080-60i 30fps

If you're filming with a rebel , get vegas 10 or the 9.0d update, helps so much. If it's a gopro, use shift+b because vegas and Mp4 don't go together great. I'm pretty sure vegas 10 works a little bit better with the mp4's though.

maybe try to preview it in a lower quality. sounds like your graphics card is just not up to the challenge of what is HD video

I never find it's my graphics card for that sort of thing, more your CPU+ram.

That's why having a tonne of memory and multiple cores is needed for editing, because trying to run a couple of effects or filters along with merging multiple setup clips is really stressful on a computer, previewing it in a lower quality will do just that and lower quality + strain on your graphics card, but if it's still fluttering around after the fixes said above you just don't have the power to run Vegas smoothly.