Adobe premiere 6 0 wont playback anything

Ash S

Jan 3, 2011
Adobe premiere 6 0 wont playback anything; I have been editing together masses of stills to accompany an audio soundtrack. I had trouble importing one particular still image but after I re-saved the image as a slightly smaller file it imported ok. Ever since I tried to apply an effect to this still, the playback no longer works - don't know if it was a coincidence? I have removed the still and tried all sorts but whenever I click on play, the curser just goes to the beginning of the timeline and doesn't play. Worryingly, Adobe Premiere now won't play other projects which I have previously worked on - the exact same problem occurs.
Does anyone know whether I have accidentally changed a setting somewhere because I am clueless to what is going on now?