Need help to sort out Champion W-Tab 7.1

I have a Champion W-Tab 7.1

Suddenly i can't open my Champion W-Tab 7.1 device

when i boot it only appear the android logo in the screen and nothing else comes .

So i can't use my device as it only appear the "android " on the screen also i failed to find to key combination to hard reset my device .

Please some one guide me to solve the problem .

Thanks !