Windows 7: Charging an MP3 player while the computer is asleep

Where do I go to change the setting so I can charge a USB device through a USB port while my computer is sleeping or off? I have a gateway DX4860 with Windows 7. My Toshiba laptop had a popup that came up and asked if I wanted to change the setting to allow charging when asleep. I haven't gotten that on the PC and can't find it in the control panel.

Thanks for your help.

Hi
It is true that there are many desktops and laptops support that USB ports left alive while shut down so that we can charge any gadget through it. I also have it with my Samsung Netbook and Gigabyte desktop. Btw, I've read your gateway DX4860 specification, it doesn't seem to support that capability. But if you want to make sure of it, you can try find out if there is power feature software/utility from the factory. If it isn't then probably it doesn't.

Kevin