Odd 7650 Any ideas???????

:-? I have a 7650 bout over a year old and it has just suddenly started actin strange like it will have nearly 3mb free mem yet when it goes to retieve an mms it will say not enough mem to recieve message and the a proggie called pcstel or somethin like dat will crash and the fone will reboot and retieve the mms ok and then sometimes it will get the message to retieve the mms but it won't actually get the mms at all sometimes if i got to retieve it manually it will and sometimes it won't this is very annoyin any ideas wha i can do i've all ready tried formattin da fone but no joy :-? :-?
please help