Sony Hardware Reset?



I have a Sony D-NF420 portable CD/MP3/Atrac3 Player and the Sound Options have mysteriously dissapeared from my Display/Menu Options. I’ve read the directions SO many times it’s rediculous. I even contacted Live Sony Support and their answer was just “take it to your nearest Sony Repair Dealer” or whatever. The thing is, my CD player HAD that option when I first got it, but days later, it didn’t show back up in the Menu selection. I know that the player itself keeps “memory” despite taking the battery (or batteries) out. (WHich I’ve left out for weeks at a time). Is there a way to “reset” the player or a resource where I could go to find out? I have a feeling that the firmware is messed up somehow…not sure how, but things like that happen I guess. Thanks for your help.