It depends, if you had internet connected before this happened, there are many possibilites.
A)Your computer has become corrupt from a bad download.
B)You recieved the "Conficker" virus during usage the day before.
If it wasn't either of those..
A)Your computer has alot of dust inside, and must be cleaned out for further use.
B)The power supply was shot.
C)Your computer has vital damage, and needs to be repaired.
If none of these comply, please PM me for further instructions.