6310 (not i) crashes

My 6310 which is about 12 months old now has developed the anoying
habit of crashing occationaly. By crashing, I mean it goes off and the
re-starts itself.
It does this at different times, but always when it is being used,
(pressing the key pad), as opposed to just in standby.
I use an HDW-2 bluetooth headset which also makes it crash sometimes.

I read alot about firmware versions. Could this be at fault?
How can I tell which version my phone is on?
Have I got to take the phone to a service centre to get it updated, or
can I do it over the web with the phones infrared?

Lofty