removing line breaks in cells

Thank you. I don't really want to remove or modify gridlines. What I want to achieve is to make sure that each line of text is on a single line in the spreadsheet. Right now a series of entries use two spreadsheet lines for each line of text. I don't know how to bring that back to one line each.

Thank you - that worked. Then I had to work out how to delete non-sequential blank rows - did it the long way! Thanks for your help.