[tsac]

You tried the battery in another BB and it works so the next thing to check is the contact pins on the blackberry. If the BB was ever exposed to water or even a high humidity environment hopefully the issue is only some corrosion on the contacts.
Check and if not then it may be the BB is defective. As a last resort you can try connecting it to a computer via data cable and see if it is seen in the desktop manager application ( free from blackberry.com). If it is seen or the BB looks like it is powering then after it does ( hopefully) we are back to the power connectors or something else internal.

Good luck