I bought a chinese iWin v91 tablet a year ago. It worked very well but when I used it couple days ago it freezed when I unlocked it. That has happened many times and the only fix for it is just to reboot it. I turned it off like normally but then it didn't go to the home screen anymore. It's stuck in the android logo every time I try to turn it on. Sometimes it goes to the home screen but turns off again soon. I tried to do a factory reset but when I press volume up and power it just goes to a screen where is a android robot lying down and red triangle above it. I can't find any menus there and if I try to press volume up and power there too, it says rebooting... and gets stuck in the android logo again. I have tried all the buttons and I just can't figure out how to fix it. I'd like to know how to fix this problem.