Try using Revo Uninstaller. Even if it can't uninstall the application normally, it will force it to uninstall by wiping out all traces of its presence from the system.
After Revo finishes the initial procedure, restart the application and then look for SprintWork once again. If it doesn't appear in the list, then it's gone.
After that, try running AdwCleaner to make sure that there are no leftover rogue registry keys or toolbars in your system.