As I wrote before, I had some problems during the upgrading of my LG gt540, while I was updating it my computer stuck and then I couldn't restart the device.
One solution for this trouble:
1. Unplug USB
2. Remove the battery
3. Hold the volume down button (LHS of phone) and reinsert USB lead at the same time
4. I then re-ran the update program.
LG Program Download
USB Driver Download
When you install the update be patient!!!!!! It takes forever