PLug your Sansa in.
Right Click on My Computer > Properties > Hardware > Device Manager > Any
yellow triangles to be seen ? If yes, for what ?
If no, can you see your Sansa device mentionned anywhere (click on the +'s
and undo the "trees") ? If yes, right click on it, uninstall it, un-plug it,
and re-boot.
Once back in XP, plug in your device. XP should then "recognise" it and ask,
in theory, if you want to install drivers. Choose the ones you downloaded..
Re-post if nothing works.
Cheers,
Jerry