The dreaded red cross on screen won't boot up helppp! What should I do?

Please help me guys i have searched internet high and low. I have the red cross on my blackberry bold when i pkug in to charge! Well atfirst the redlight comes on then the normal battery sign with bolt through it then the redcross appears and phone just wont boot up atall!! I have cleaned all connections and pratted about with the battery in so many different ways.! I have tried leaving on charge and doin hard reset and reinserting battery and still nothing... but it has had this problem a while but i have had it goin once again but then battery went fully dead and now i cant get it goin again.. i have heard of this dropping and wacking the hell out of it but still nowt! Unless you have to do this at a certain time to make it happen.., someone help lol x

If you battery is three or more years old, which I assume it probably would be, then don't overlook the obvious possibly that it is simply knackered.

Lithium Ion type batteries have a finite lifespan whether they are used or not. Mistreating them (eg. letting them get hot, letting them deep discharge, impacts) will accelerate their decay.

If the battery is showing any signs of swelling then dispose of it immediately at a suitable recycling point.

Don't continue trying to use a knackered battery. They are a genuine fire hazard, as the many Internet videos will attest.

Unfortunately, a replacement battery will likely have been manufactured some years ago for the Bold, so a 'new' one will already have lost some capacity that it had from manufacture. Still, it won't have been used so still should work for a while.