Sansa Clip 1GB - Shows on PC in My Computer but cannot open software to install podcasts, etc.

Hello.  Your help would be much appreciated with the following little problem.  Apologies in advance for the long saga.

I have had this unit for some months and it has worked fine; I use it mainly for playing back podcasts whilst I am walking my dog.  I recently had the unit connected to my PC (2 years old PC running XP) and loaded on some new podcasts with apparent success.  I then disconnected the Clip player and found that it would not respond.  It showed that it was connected but still writing data but would not otherwise do anything.  I left it plugged into the PC in the hope that it would sort itself out but when I came back a few hours later I found that all that had happened was that the Clip’s battery had gone flat, although it still showed as being connected and writing and the battery indicator was flashing.

I disconnected the unit until today when I thought that I would make a concerted effort to get the thing working again.  Having read a few posts on this forum site, I tried pushing the slide switch at the side of the unit into the top ‘on’ position and holding it there for 20 seconds to reset the unit.  This did not appear to do anything, so I tried doing it a few more times but no obvious result.  I then connected the unit to the PC and although it still showed ‘connected’ and occasionally ‘writing’ and would do no more, I left it connected whilst I …walked the dog!  When I came back the battery in the unit seemed to have mostly charged up and it would respond to play back commands when not connected to the PC - progress!  However, it did not show up as existing to my PC; the usual software screen did not appear to allow me to check the contents of the disk and the unit still showed ‘connected’ and ‘writing’.

OK, so then I read some more from this site and tried connecting the unit to the PC whilst the unit was turned off and whilst I was holding down the centre button.  The unit then appeared on the PC under ‘My Computer’ - more progress!  However, nothing appeared to be in any of the folders shown and no software appeared to allow me to insert some new podcasts, whilst the screen on the unit still showed ‘connected’.

Any suggestions that you may have would be very welcome, as to how I can get this unit to function correctly again.  At the moment, the radio works and the unit will play back the few factory installed tunes that seem to be left on it but I cannot either find my old podcasts or install any new ones.  Thank you in advance.