|Technically, I shouldn't answer this question in this thread since we prefer that each question be in it's own thread so that it can be found in the archives.|
In this case, I'll bend the rules since I assume you are trying to highlight the drawing numbers that have the higher rev number on Sheet1 vs. that which was found on Sheet2.
What you are looking for is a feature called Conditional Formatting.
- Select the cells in Column A that you wish to apply the formatting to. I'm going to assume that your selection starts in A1.
- Click on Formatting...Conditional Formatting
- Select the first Drop Down and choose Formula Is...
- In the right hand field enter the following formula. (You can copy the formula from this post and paste it into the field with Ctrl-V. You can't paste it with a right-click, but Ctrl-V will work.)
- Click the Format button, then the Patterns tab and choose a color.
The Conditional Formatting will be applied to all of the cells that you have selected and update the formula automatically.
Whenever the condition spelled out by the formula is TRUE, the formatting will be applied.
In Excel 2003, you can have up to 3 Conditional Formats applied to a cell.