You can deactivate the links through Office button and the Excel options button, see Turn off hyperlinks.
Hyperlinks can be found through the search function, see Finding Excel hyperlinks. Quoting from the source:
Using the Find Feature
A quick way to cycle through your external
links (depending on the number you have) is to use the find feature
built into Excel. We will be searching for “[“, left bracket, which
can help identity those external workbook references.
- Hit Ctrl+F (or Edit–>Find on your toolbar) on your keyboard to open your find wizard
- Click the “Options” button to open additional criteria
- Select: within “Workbook”
- Select: look in “Formulas”
- Finally, enter a left bracket “[” in the Find What field (without double quotes)
That’s it. Excel will now go through and show you all the instances
where the left bracket has been used in your spreadsheet, which should
identify external references to other spreadsheets.
Delete Links Add-In
Microsoft has also provided an add-in to help you
identify and delete links. To view Microsoft’s solution to this
problem, visit http://support.microsoft.com/default.aspx?kbid=188449.
There is an additional Read-me file to help you use the add-in after
you extract from the exe file.
The reason the Find Feature works is that external references are identified by a set of brackets. However, the feature also finds whatever left brackets you might have on the document, not just the ones corresponding to external references.