an reset or an update might fix it, but if it doesnt, its still under warranty!
turn on your 5310 and locate the reset on the bottom left of your unit (small pinhole) use a paperclip to insert and depress the reset switch.
if that fails and you want to try an update, you can get the 4.72 update HERE
you have to sign in and register before they will let you download anything.
to send it in for warranty repair or replacement call the number listed below.Hours:
Monday through Friday, 6:00 a.m. to 5:00 p.m. PST/PDT
800 707 9971