The problem seems to be related to Internet Explorer 8 performing a search of network drives and your local area network and any disconnected network drives or LAN search issues will hang the loading of your Excel spreadsheet.
Here is how to stop Excel 2010 from browsing your LAN / Network drives when you open an Excel spreadsheet on your local hard drive:
1) Start Internet Explorer 8
2) Go to "Tools" menu
3) Go to "Internet Options"
4) Go to "Security" tab
5) Go to "Local Intranet"
6) Click on "Sites" button
7) Uncheck "Automatically detect intranet network"
Now your Excel spreadsheet should open instantly.