Phone rebooting at startup

[Agent86b]

Hello all,
I have a Nokia 6600 with Mobile Speak that has been working perfectly
until I turned it off last night.
Each time I start the phone it will either load all it's software and
get the signal then reboot. Or it will get to the Nokia tune then turn off.
Can anybody please tell me if you think the phone is terminally ill
or can I do some kind of reset to restore original settings. If I can
restore the phone I then would try and do a restore from my PC Suite backup.
Hope someone can help I would prefer not to purchase a new phone at the moment.
Thanks for any advice.
Max.
Max.