I am going to add the following code in a Code Tag, it is mentioned in the reply window with a Hash(#) Sign.

Try this:
Sheets("2013 Budget").Range("PAr").EntireRow.Hidden = not(Range("L1").Value)
Let me know if any error is thrown or works just fine. I still believe that your box is not linked to "L1" so L1 is never true. Can you please recheck if the box is changing value in L1 or any other cell.

Thanks,
Vikas B