In order to utilize Excel sheets that have macros function properly, you must ‘enable macros’ in Excel itself.  By default, in Excel, macro’s are disabled.  It is my recommendation that you select the lowest security setting for macros (ie. have them permanently enabled) so that you save time by not having to constantly turn them on when you open new sheets.  It ‘can’ leave you vulnerable to running macros that contain malicious code, but the simplest way to avoid that is to only open Excel files from known, trusted sources.  Basically, it all comes down to common sense.

Note: This procedure is for Excel 2007/2010 only
If you are unfamiliar with the process, the steps are:

1. Click the ‘Office Button’
2. Click “Excel Options’ at the bottom
3. Click the ‘Trust Center’ tab
4. Click ‘Trust Center Settings’
5. Click the ‘Macro Settings’ tab in the new window
6. Click the ‘Enable all Macros’ button

See the following PDF for a visual guide:

LTS_Tech-Enable Macros.pdf