Problem when starting computer

[Santirep]

I have installed Windows 8 in a computer that was given to me at the school (Argentina) and when The Windows start (I supouse) just a second before the windows' logo appear it shutdown, then I start te computer again and everything goes well, then next time I tried to start it, it crashes and then it start well
What can I do??
It crashes exactly when windows' logo have to appear, and it only turn off instantly, No Blue screen or nothing
I hope you understand my english!