i have blackberry 9000 bold ,some day before it become dead, means there is no red light on,no computer connection, solve my problem and help me.

take it apart, clean any connection, put it back together, get a different battery, different charger. do anything.

Reboot your phone and try again

I do not recommend taking it apart. If you aren't skilled in that sort of thing, you can do more harm than good and brick it.

Do you mean the battery dies and the phone shuts off? That is the way it is supposed to work.

Does it do this on a regular basis? How long has it been on when it happens?