my dell venue8 3830 tab stuck to dell logo.

Two days before i was using my twitter account and suddenly my tab got hanged, I waited for half an hour but still the tab was in hang mode so switched it off and tried to on but after pushing the power button only dell logo was coming. I tried to push the volume up + power button and volume down + power button simentaneously but both the techniques were not working . Next day I brought my tab to nearby dell centre and they said that the Oprating system was corrupted . Still I am in trouble because they handover my tab to me by saying that may be their is a problem in the mother board . kindly suggest me the solution because my exams are near and it would be difficult for me to study without my tab.