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Please tell me more details about this problem. Does it only occur on certain spreadsheets? Does it occur if you simply open Excel (with no sheet)? Any system changes or did anything happen just before this problem started? Are you opening these sheets over a network , or on the same computer?
1. Click Start >> Computer.
2. Double click C drive >> Program Files >> Microsoft Office >> Office12.
3. Right click EXCEL.EXE and select Properties.
4. Click on “Compatibility” tab and uncheck the check box “Run this program as an administrator”.
5. Try opening Excel.
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