1.
Start Excel from the main program. Sometimes a shortcut to a program can become corrupt and cause the application to have problems opening. Go to the 'Start' menu, click on 'All Programs' and find Microsoft Excel in the program list. If it opens properly, delete the problematic shortcut by right clicking it and selecting 'Delete.' You can make a new shortcut by right clicking the main application and choosing 'Send to Desktop.'
2.
Disable add-ins. Sometimes these optional programs are problematic. In Excel 2007, click the 'Office' button. Click on 'Excel Options' and select 'Add-Ins.' In Excel 2000-2003, go to the 'Tools' menu and select 'Add-Ins.' If you disable them and the problem is solved, enable them one at a time to determine which is corrupted.
3.
Let Excel find and fix the problem. If you are using Excel 2000-2003, go to the 'Help' menu, click on 'Detect and Repair' and then click 'Start.' In Excel 2007, click the 'Office' button, click 'Excel Options' and then click 'Resources.' Click 'Diagnose' and then click 'Continue.' Click the 'Start Diagnostics' button. Excel will look for potential problems and repair them, if possible.
4.
Perform a 'System Restore' on your computer. This will restore your computer to an earlier date and time when Excel was working properly. Click 'Start' and then 'All Programs.' Point to 'Accessories,' and then 'System Tools.' Click 'System Restore,' and follow the wizard's instructions.
5.
Uninstall Microsoft Office and then reinstall it . Go to the 'Start' menu and then to the 'Control Panel.' Select 'Microsoft Office' and uninstall it. Use the Office disk you used to install it originally and reinstall the software.