I am using Blackberry bold 9000 for last 1 year, recently I was having some problem with it. In one fine morning my phone was in hung mode. So I did a routine battery pull. While blackberry was rebooting, the progress bar on the loading screen went to 1/3 and then the phone rebooted again. The process goes on and on and at the end the phone got dead. If i hook the phone to the wall charger I am getting the same thing. I took out my SIM card and memory card but no use. I have tried every possible thing to troubleshoot this problem.
In short my BlackBerry was stuck in a permanent reboot cycle and it was completely unusable.
At the end I have decided to reload Blackberry OS to fix this problem.
Pre-requesites:
1. Blackberry Device OS 5.0. You can download the same from here or else do google search for download blackberry os 5 for blackberry bold 9000
2. Data cable
A. Remove battery from the blackberry device.
B. Install Blackberry Device OS which you have downloaded earlier.
By default it will get installed in C:\Program Files\Common Files\Research In Motion
C. Now go to C:\Program Files\Common Files\Research In Motion\AppLoader and rename Vendor.xml to Vendor.xml.bak else you will get the following screen while reloading your Blackberry OS.
Note : We have renamed vendor.xml because we are getting the blackberry desktop software does not have blackberry device software for the device that you have connected to the computer error
D. Now double click on Loader.exe. You will get Loader.exe in C:\Program Files\Common Files\Research In Motion\AppLoader folder
E. Click on Next button.
F. In next window you have to select Connection as USB-PIN: UNKNOWN from drop down list.
G. If you have set any password earlier you have enter the same in next screen
H. In the Device Application Selection screen, you have to select language and application you want to install on your blackberry Device.
I. In next Windows it will show you the options summary you have selected.
J. Now it will start updating your device.
On device you will see following screen
K. Now here is the trick. While doing above process I have removed battery from my device. We have to put the battery back in the device when you see Wait for device initialization in Application loading wizard.
L. Once the device initialized successfully it will start loading modules in your Blackberry.
M. After a successful installation you will get the completion message. That’s it. Remaining configuration you have to do on your blackberry handset.
My name is Vidyadhar Sarmalkar & I work as a consultant and have done RHCE & CCNA. 
