Beginner to the forum and must say - this is a GREAT resource!! Learning so much just browsing!

Here's my question:
I am pulling a new workbook (1 sheet) twice per day. I already have a macro that does my sorting, etc.. But now I want to include conditional formatting to highlight all the rows that have a timestamp in column A that is x hours old (21 hours). My format is m/d/yyyy h:mm. Seems the preformatted values only include days and I can't figure out how to write a formula for hours. Oh and i also want the formatting to stop at the end of the data - seems to want to keep highlighting all the way to the bottom.

thanks in advance for any and all replies!!

Paul