Does anyone know of a problem editing block code from the block admin section?

I can view the code and edit, I then click View... The page refreshes but nothing alse happens, im guessing its supposed to be a preview in a popup?
Ive tried all the basics like allowing popups and different browsers but all are the same.

I also tried uploading the relevant file with the changes but it still shows the same

Where can i look? have i missed something?

Also how do i set up files to alter the site using templates, I'm thinking about the main menu and adding links.

You have to first clone your templates to edit a block template. The preview button has never done anything for me.
Maybe it's there for future feature??

You clone your templates in Admin Templates. Once you do that you will have a submit button to save your changes. If you make a mistake you always have the default, noneditable templates to fall back to.

HTH.