Viewport moving issues!

Ok I'm sorry if I'm reproducing any previous posts but I've searched everywhere for the answer to this problem, and I think I can't find anything about it because it's really hard to explain.

When I got back to my computer yesterday after a break I tried to move an object, only to find that instead of the object moving the view moved. I also can't rotate, scale or select a different object. I have tried restarting C4D, using a different file, restarting my computer and just shouting at it - all to no avail. (apparently threatening to reprogramme it with an axe doesn't work...) I've gone through all my viewport settings and it doesn't look like anything has changed.

I really am completely clueless with this one and a bit desperate cuz my deadline is tomorrow!