How can I global reset the 7610 ?

This would be the same as the 6600 and other symbian phones.

6600 Reset info here

" JUST TO THIS"

Normal Reset (*#7780#) : Restores ini files from rom but preserves user data (photos, 3rd party apps etc)

Deep Reset (*#7370#) : This reformats completely the C: drive. All applications and files stored on this drive will be lost and clean default files will be rewritten.

Full phone format on a 6600

If any of the problems listed below is happening to your phone:
A. Blank screen phone unable to boot-up.
B. Phone is only able to boot-up to "Nokia" screen (may flash "Nokia" 4 times also).
C. Install a program but unable to uninstall it.
D. Unable to delete certain files on C drive.

--- WARNING: This will ERASE EVERYTHING on your phone ---

If you have any files that are important to you, make backups.

1. Make sure you phone is fully charged.

2. Backup your contacts list and personal files to MMC memory card (if possible).

3. Switch-off your 6600 phone.

4. Press and hold these three keys together

-Green dial key,
-Star key (*)
-Three key (3)

then press the power on/off to swtich on the 6600 phone.

Do not let go the three keys until you see the "formatting" screen displayed

5. After a few minutes, the format will be complete. Your 6600 will now be at its original factory settings.

Thanks that did the trick!