Hide Rows based on Client Drop Down List

Hello All-

I am a horrible newbie. I have a Data Validation dropdown list of clients in a time sheet. Then I have 5 sections for weeks of time entry.

Row Ranges for Time Entry:

9:29
33:54
58:79
83:104
108:129

Within these ranges, column C has the client name that matches the dropdown selection.

What I want is to select a client from the dropdown, and hide all other rows...so I can print a time sheet for hours billed to the selected client.

If I choose "none" from the drop down...the all rows should be visible.

Where do I begin?

Thank you!

Troy