Editor broken down

Out of the blue my editor has stopped with most of it’s functions. When I am in the visual mode, I can only add and delete text. I can select text (but not with the mouse??), I can select the ‘make a list’ button (with the mouse) but it will not make a list. I can select the ‘make a link’ button, but it will not open the next frame where you can actually enter a link. Same with ‘headings’ or ‘bold’ etc.

I haven’t installed a new version or new plugins. I have just been updating pages and posts, added a picture to the library, made a new menu-item and trashed a post.

I have been working in a different browser (Safari on a Mac) when doing this though, might that make a difference?

I thought it might be a temporary thing, so waited a week, but that didn’t help. The rest of my computer works fine, so it’s not like my mouse is broken.

Any ideas where I even start trouble-shooting? I would be so grateful for any help.