Any Ideas???

I have Photoshop 7.0 and today after I started working I realized there were two problems. Problem one is that when I was using a .psd and was dragging the a layer (for example a selective coloring layer) it wouldn't move, that was when I tried it on a new document - but when I used it on the original it worked fine. It did not do this before. My second problem is that when I got to save I no long have the .png option. Does anyone know how to get that back? And how to fix my dragging problem?? Thanks in advance to anyone who helps, if you have any questions, please ask so I can fix this.

***problem fixed. thanks for your help.***