Have you tried repairing WLM. To do so go to control panel>programs and features then scoll down to Windows Live Essentials right click then click on the unininstall/change that appears, you will then be given an option to uninstall or repair all of windows live essentials choose the repair option. It is a good idea to back up your emails before doing a repair, though I have never lost any but some people have. As for the sfc /scannow, type cmd into search box, right click on the cmd then choose run as administrator. In the window that opens, type or copy and paste "sfc /scannow" without the quotes and press enter. I would try a repair as your first option.