HELP!

I have photoshop 7 and just recently I went to save an image and when I did - the box that shows up - the one where you can decide to save images and such -completey froze up photoshop - I can't cancel the box - when I click on things it doesn't work - i cant save - i can't change folders - and I can't exit out of photoshop - I have to turn off my computer and start all over again.

Does anyone have any tips?