Panel memory doesn't save after shut down

Please can you help, I have been a bit remiss in not playing too much these days due to domestic problems, but i did get a chance the other day and found that when i had saved into a bank, re named the bank and the file that was OK until I switched off, when I powered up again it had all gone and the original was back again ! Is there something I have missed ? I re read the manual several times,but could not find a save anywhere,or a delete file button , so I just assumed once you had selected the bank put in a selection into one of the 8 buttons then re named the file again you were overwriting the original and you pressed the OK button it was done
Hope it is a silly mistake by me and not something serious. many thanks for any replies ken