Cursor is a do not enter symbol

[shinersview]

Help.  I keyed ahead and apparently hit the wrong key somewhere.  Now my cursor looks like a road sign "do not enter" (circle with diagonal slash in the middle).  I can't do anything.  Have saved the file and reopened and still have the same issue. Can someone help me figure out what I did and how to fix it?

Thanks!

[Peter Spier]

Sounds like you've inadvertently locked either the frame or the layer.