PowerPivot add-in box won't stay checked
I recently downloaded PowerPivot add-in for Excel 2010 and ran the install. I went into the options & found the add-in in the COM Add-ins. I clicked the box and the check mark appeared in the box. However, the ribbon didn't appear. I closed Excel & re-opened it. I rebooted the computer. Nothing worked. When I looked at the add-ins again, the box was not checked. I can click it & make the check mark apprear, but it goes away as soon as I close the window.