Whin i downlode a music file right tere my cpu was spark and than i can not star

There was a spark in your computer? Probably came from the power supply I suppose. Anyway if that's the case, best case scenario the PSU is dead and needs to be replaced. Worst case scenario, it sent a current spike through your system and killed off more components.

Easiest thing to try is getting/borrowing a new power supply. Otherwise you might need to take it in for service.