Excel automation

The scenario: I have a master list of companies in one Excel workbook. I have another workbook open that contains a general list of companies. I need to find any companies from the master list that show up in the general list and mark them through some sort of formatting (font color change, fill, etc). Is there an easy, automated way to do this? Note: I'm still a noob when it comes to Excel.

Thanks so much for your time and help.

Thanks Martin!