Friends, my sony don`t seem to "listen" to me any more. Ring tone switches to 'default' after every reboot and also shortcut/widget of the Apps that are installed or moved to my SD card will get wiped out from the hoem screen
That does sound pretty annoying. I'd have to think your only resolution will be factory resetting the device. You'll want to backup everything before handling this, and then you can restore content to the device. Chances are good that your problem will go away, unless it has been caused by hardware. In that case, you could try swapping out the old SD card for a new one. Perhaps it has become corrupted and is causing most of your present issues.
I think if you try factory reset, it might do it, if not you might want to check if all the hardware parts included are well working, you can do a check by taking it to a shop, but don't do that unless you've tried factory reset at first.