The n70 was never the fastest phone.
time settings normal ?
is your memory card full ?
did you had a "contact service" message on the screen ?
was the phone sim locked ? (if it was, the formatting could lock it again)
if the card is full, removi it and try to start the phone
since when is the "no service" problem ?
andthing happend to the phone ? (like dropped or something like that)
make a backup of the settings and the phonebook and reset the phone - if that wont help - there is the possibility of a hard format (without sim and memory card - battery has to be full - connecting the charger would be even better)
1)switch off your phone
2) press and hold these 3 keys together: green dial key, the star key(*) and the number 3 key
3) Power on the phone
do not release those 3 key until the regular shaking hands animation starts (that means: leave your fingers on the buttons even if there is something about formatting on the screen)
the next thing you should do is to update the phone - the software is on nokia.com
after the successful reset and update you can write back your contacts