BArrery chatging is best done using the original BlackBerry wall charger. This (do a forum search) gives the fastest charging and longest battery life.
USB charging of Blackberrys mostly works but the BlackBerry draws power to very close to the USB limit that some PCs complain whilst others work fine.
I believe this issue is related to the USB Power Management options on your computer. There's a power saving option for most USB controllers. When the power saver mode is selected the USB ports are not fully powered so when you try to charge a device via USB there might be insufficient power to charge the device.
Long story short disable (uncheck) any power saving mode options. Sometimes installing BB Desktop Manager will address this issue for you.
I believe this issue is related to the USB Power Management options on your computer. There's a power saving option for most USB controllers. When the power saver mode is selected the USB ports are not fully powered so when you try to charge a device via USB there might be insufficient power to charge the device.
Long story short disable (uncheck) any power saving mode options. Sometimes installing BB Desktop Manager will address this issue for you.