BB Bold :: 9780 Shows Only 5mb In Applications

I have a Blackberrry bold 9780 for the past 2 years.I have configured 4 email ids on it.For the past few days i have noticed that it has started hanging on me.Even after doing a hard reset it still hangs so decided to take a backup. when i connect it to blackberry desktop manager it connects after a few minutes but as i start to take the backup it goes off and restarts.i need all these mails as they are all very important to me.I managed to connect and take backups after a few unsucessful attempts.I noticed that after conecting via the blackberry manager and going to appications that the device only 5 mb remaining out of the 500mb storage.There are no appications installed other that my mails.Now my question is how to free up space in the phone as the phone is almost unuable.I need the mails as i have also added a flags to my important mails which are older that 2 years

1)Is there a way to delete mails that are not flaged.??
2)can mail storage be changed to media card???
3)Can these mails which are there be synced to outlook ???
4) what are my other options other than going to a newer decive with more storage.

I am using the phone with the blacberry services turned off.

Also I have tried uninstalling blackberry protect which all of a sudden showed up in the appications via blackberry destop manager the space is now showing 3mb left out of 500mb after the phone restarted.