Sansa clip+ completely unresponsive

2 of my 4 SansaClip + are completely unresponsive, except for the message I get on my PC stating “you need to reformat the disk in drive E before you can use it”. Neither of them will respond to any of the usual methods of getting started, ie hold start button for 30+ secs then press again, hold centre button for 30+ secs etc. I’ve been through all of the various tips to get them up and running again without any success. 1st of the 2 lasted for just over 12 months before starting to play up, initially faltering over starting to charge and eventually not responding at all. 2nd of the 2 was bought as back-up for my original (which was 3 years old, and is still working fine) and stopped working without any warning after about 4 months. Is there any future in reformatting as my PC suggests or will this knacker the 2 clips completely?

Reformat it with the pc, but then later reformat it again using the player’s menu.