A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
You should base the conditional formatting rule on a formulas like,
=$X2=123
... and make sure that the Conditional Formatting Rules Manager shows an Applies to: range of something like,
=$D$2:$D$39
Finally, make sure that the rule has not been copied to other cell ranges by accessing Show formatting rules for: This worksheet. Conditional formatting rules get copied and pasted into other cells much as conventional cell or cell number formatting does.
If you can be a little more specific about 'if something shows up in Column X of that row', I may be able to offer more precise directions.