Ok, It happened to mr before.
Please follow the instructions below carefully and you will be done:
1)Install the latest OS or any OS you have.
2)Delete the vendor file if you find it in Common files» Research in motion» AppLoader folder.
3)Connect your device to the PC.
4)again go the the same folder Common files» Research in motion» AppLoader and double click the file Loader.
Then follow the instructions and your Bold will be fine.