I've started having a problem with Excel 2007 SP1 under Windows XP
SP2. When I attempt to open an existing spreadsheet (any spreadsheet
I've tried both xls and xlsx) by double-clicking on the file, Excel
opens, but the spreadsheet doesn't display.

When Excel opens the menus are there, as is a disabled quick access
toolbar and all of the frame and "Ready" in the lower left corner.
However there is no grid, and no data. I can make the grid and data
appear by clicking on another window, and clicking back on the Excel
drag bar, by clicking on the Excel formula bar splitter, the "Office
button", the Macro recorder gadget or Customize Quick Access button.

If I open Excel without a document, it opens normally and if I open a
document from within Excel, that's fine too.

This all started happening AROUND the time I upgraded Norton Internet
Security from 2007 to 2008. However, the problem persists if I disable
Auto Protect in NAV.

Kevin