looks like it's a HD project. But the pic, and you, don't say anything about what's going on, just that you're not happy. Not having your system specs filled out doesn't help either.

common solutions: files you're editing aren't good to edit (non-DV/HDV files), file drive is on is slow (firewire or usb drive), processor can't keep up, cpu intensive FX on clip... list goes on.