I have my Nexus 7 tablet rooted but when I try to delete the APK for either Google Pinyin or the Korean Keyboard system apps with either Astro or ES File Explorer I get a message that the file cannot be deleted. As I do not use or need either of these apps and I am getting frustrated about receiving update notices all the time for the Google Pinyin I'm hoping that someone on the forum can shed some light on how to permanently get rid of these apps.