hi I've had the same issue on a similar tablet to yours. It took me a while to sort it out, and the issue is often a corrupted or disables sytem file - most commonly caused by using root apps like 'Pimp my rom' or in my case 'ROM DIY'. The solution is often simply to re-enable the file that has been disabled, and reboot. If this is not possible e.g the apk was permanently deleted or is corrupted, then removing DEMO is much harder, but is still possible. There are 2 ways, descibed below; both require a rooted tablet which can be easily done with 'unlock root' in windows. If your tablet is already rooted simply install SuperSU and grant yourself superuser priviledges:
Solutions:
1. Riskier but will restore tablet to new - Download the appropriate firmware (or ask the vendor for it) and flash the rom (usning phoenixsuite). Make sure the firmware matches your tablet of you run the risk of bricking it, or you may end up with some features e.g wifi or touchscreen not working correctly
2. Less risky but not perfect (this is what I did) - install 'Rom DIY', 'back button', 'battery widget', 'wifiWidget', 'wallpaper changer' and 'popup free'. Set these apps to run at boot (using their own settings, when available, or the 'Accessibility' tab of the tablet settings). When all the apps are up and running, use 'rom diy' to disable 'systemUI' (it has the jelly bean icon) and reboot (full reboot, not quick). This will cause the DEMO to disappear but you will also lose your wallpaper, navigation bar, notifications, and notification bar (where battery status and network connection are displayed). The various free apps mentioned above will restore the missing functionality and with some minor configuration your tablet will look even better than before.
The browser homescreen is a seperate issue. You can use ROM DIY (on a rooted tablet) to disable the stock browser and install one of your choice (e.g dolphin or chrome) which will be unaffected by this issue.
Hope this helps,
Gabe
08-24-2014 03:29 AM