Another possibility: If the OS install failed, take out the battery again and put it back in. Hopefully the hour glass will go away and you will get a rectangle with three symbols within and a numbered error message beneath. If so, you can reinitiate installation of the OS without Javaloader.
Desktop Manager will not recognise your crippled Blackberry but go into the Applications Loader and ask it to find device. It will say no device found and suggest COMS 1. Click on that suggestion and it will find your Blackberry and display USB and your PIN number. You can then proceed with the load.
This is a smart feature of the 8700. Even if the OS has been wiped and the new installation failed, the communication protocol is retained somewhere deep within and recovery is possible.