Same thing happened to my wife's Sansa and her computer. But, my 
computer worked with the Sansa. She only used her Sansa for audio books 
from audible.com . The fix was that I uninstalled her audible manager 
software for audible.com and then reinstalled it.

Although your details are somewhat different, perhaps my experience will 
give you a lead to a fix for your problem.

Tom

Don Penlington wrote:
> I have a Sansa Mp3 player.
>
> It connects to my computer (XP Pro) via USB. It was working fine last 
> time I connected it 2 months ago to transfer some music files to it.
>
> Now, it does not appear in My Computer so I can't open it.
>
> Device Manager identifies the Sansa under "Windows Portable Devices" 
> and indicates that the device is working.
>
> The Sansa lights up when plugged into the computer.
>
> In Control Panel there is an entry "Portable Media Devices". When I 
> open that, it is empty.
>
> I have rebooted, and unplugged and replugged the USB connection. Tried 
> different USB ports. No difference.
>
> I have looked thru BIOS settings, but do not see Sansa or any USB 
> device settings anywhere.
>
> I have switched the USB ports between my USB printer and the 
> Sansa---both ports see the printer OK, so I assume the USB ports are 
> functional.
>
> What has happened to my poor little Sansa? It lights up when plugged 
> into the computer, so I assume the connection is working.
>
> Don Penlington
>
>
> From the Beach at Surfers Paradise in sunny Queensland.
> Computer tutorials, local scenery,  and other things at my website:
> http://users.tpg.com.au/deepend/index1.html
>
>      

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