Sorry for getting back on this one, but I have the same problem as well, and all the fixes you suggested don't work (clearing cache, uninstalling previously installed apps, etc.) Download manager is enabled as far as I can see. The problem might be that my google account is not listed under accounts, nor am I able to add it manually. When I click 'add account', google is not listed as an option. I can log into play store through the browser. When trying to install apps that way, it tells me that certain apps are installed, but they don't list in my app manager. I don't get a download notification. Does this give anyone any ideas? Thanks!