In case you are working with ActiveX Controls or Macros in Excel , you need to have Developers Tab visibile in your Excel 2007. When you start using Excel 2007, developers Tab is not visible , however you can set it visible with following steps

Step 1 - Click MS Office Button
Step 2 - Click Excel Options
Step 3 - Click Populor
Step 4 - Tick Show Developer Tab in the Ribbon check box
Step 5 - Click Ok

Step 1 - Click MS Office Button
Step 2 - Click Excel Options
Step 3 - Click Populor
Step 4 - Tick Show Developer Tab in the Ribbon check box
Step 5 - Click Ok