Format a row when user hits enter

Hello All, I'd like to have a use fill out a table and when then get to the last column and hit enter it returns to first column and formats the row the way I need it to be. That is border set, cells merged, alignment and font set. See the attachment. I'm also kinda new to Excel VB so I really need an explicit instructions/code. So look at the attachment for visual explanation of what I want to do and the spreadsheet itself.

Thank you in advance.