I have a Google Nexus 7 tablet, and when I want to use my yahoo email account, my password is already there. I signed in, signed out, unchecked the "Keep me signed in" box, erased my password, but it keeps putting it back in when I try again. I don't want anyone else to be able to access my email. Anyone know how to fix this? (I don't have the same problem when using my desktop computer.) TIA.