Greetings, I have a Rio Nitrus MP3 player that I am having difficulty using on my computer. I have the latest firmware update but when I go into Rio Music Manager (player softwware), it isn't there. It does show up in Device Manager. I tried doing a reinstall of the firmware on my computer but kept getting an 'invalid handle' message when trying to upgrade. I was able to take it to my girlfriend's house and install the firmware from there and also use the player software so the problem must be machine specific (mine) that makes it unusable. It doesn't be design show up as a removeable drive in Explorer as I could transfer music that way. I've tried all my varios USB ports, hubs etc. to no avail. I also have a Rio Carbon which works fine on my system so I'm baffled. Any help would be greatly appreciated. Muchas gracias.