More than likely you or someone you know has experienced the pain and annoyance that is when Excel crashes. There is nothing more annoying than working in your spreadsheet, making good progress, when bam! The worksheet crashes. And while there can be multiple reasons for Excel crashing on you, the most common cause is the simplest - COM add-ins.
COM add-ins are add-ins are often third party additions to Excel that add custom functionality. So if you are crashing in Excel, try disabling your COM add ins by doing the following:
In Excel 2007:
Click the Office button > Excel Options > Add-Ins on the left side of the dialog. Then click the drop-down arrow at the bottom of the dialog box and select "COM Add-Ins" from the list, then click the GO button.
In Excel 2010:
Click File > Excel Options > Add-Ins on the left side of the dialog. Then click the drop-down arrow at the bottom of the dialog box and select "COM Add-Ins" from the list, then click the GO button.
What comes up is a list of COM-Add Ins that are loaded and running. In order to stop them from running, uncheck the boxes next to the COM add-in and then click OK. Now go back to what you were doing in Excel and if the crash no longer happens, the problem was one of the COM add-ins you had loaded. You can narrow the list down by re-checking COM add-ins in the list until you find the culprit. At that point, check the third party manufacturer's website for support options. Look for an updated add-in or look in their forums to see if others have experienced the problem. You may have to live without the COM add-in that caused the problem.