If this problem occurs on this one PC, with different Excel files containing a logo, not just this one file, then I would consider an Excel 'Detect and Repair" (not sure if it's the same term in Excel 2007).
In Excel 2007:
Click the Office Button and select Excel Options (at the bottom of the Office Button dialog box)
In the Excel Options dialog, select the Resources tab on the left
Click the 'Diagnose' button next to 'run Microsoft Office Diagnostics' and follow the instructions