Reinstall SMemo

Try pulling the battery and restart or in settings >applications > scroll to right toget to disabled apps it may be there.
 
When I open Settings, at the top I see "Connections", "My device", "Accounts", and "More". Nowhere do I see "Applications" or "Disabled Apps"
 
First select "more" then scroll down to application manager. Tap on Application manager then flick the pages to the left until you see "disabled". You may find the missing app there.