If Excel Online is not working and you see errors Couldn't Open the Workbook, or Request Was Taking Too Long, then see this post for the fix.

QUESTION:A while back, I installed a shareware program called 602 pc suite 2000. The program must have altered the way I log into Windows Explorer to read my Microsoft Excel files. When I do so, I ...

Open your first instance of Excel, and then right-click the Excel icon on the Desktop taskbar. Hold down the "Alt" key and select "Excel 2013" from the pop-up menu.