See my post again. Has there been any physical shock to the device? Moisture?
Remove the battery again, and remove the microSD card, if you are using one. If it's a GSM model, remove the SIM card as well. Wait a good two or three minutes.
Keep the cards out and replace the battery. What happens? If the device boots normally and all looks ok, replace the SIM if you are using one and try again. If all is still good, replace the microSD card and try again. If you have problems when the SIM is installed, see your service provider about getting another one (if you use one). If the microSD card is the problem, search the forum for troubleshooting tips.
BUT if you got the blackberry wet or damp, it may be too late. Se blackberryfaq.com on what to do if you get your blackberry wet.