Can the phone memory of my Nokia 6600 (old model) that has been formatted be retrieved, more specifically I wish to have the contacts and sms files, perhaps by PC software like OVi or PC Suite. These data files were not stored on Memory card or Sim but phone memeory.

this code will not fully format your phone memory, you need to do the hard format (3-keys combo code) instead. turn ONyour phone while holding together the green (call) button, *, 3 - reprograms your phone memory to factory default. all files will be deleted. you will be ask to input your security or lock code to proceed with the phone memory format. backup your messages, contacts, and other important data before proceeding. NOTE: applicable only to Nokia Series 60 2nd edition and above phones (N6600 and up) hope it well helps you

Im not sure about retrieving files, but if your handset does have a sw issue, then formatting the phone memory will not fix it.
You need a full fw update.
Get it from Nokia website here...
http://europe.nokia.com/support/download-software/device-software-update#

Note: if and when you do update, any files you had previously will be gone for good (unless they are on the memory card of course)

You cannot explicitly see the messages stored inside your phone as like the other mp3/files. In message setting choose the message storage location as memory card and move all your message to a folder created in your memory card. Then you can use this memory card to get back all your messages later.

Formatting on your 6600! as steps below,

1. Make sure you have at least 3/4 charge of battery power left.
2. Backup your contacts list and personal files to MMC memory card.
3. Switch-off your 6600 phone.
4. Press and hold 3 keys;
Green dial key, * (star key) & no. 3 key and then press the power on/off to swtich on the 6600 phone.

Remember, do not let go all of the keys and hold keys until you see a formatting word screen show!

5. After a few minutes when the Full phone formatting completed, your 6600 will back to original system and factory setting.

your phone might had ben infected by virus... try to scan your memory card in your pc, if there will virus found you must format your phone and memory card... backup firstyour files... hope to help..

My friends i suggest you to format your memorary card here are the steps:
Make sure that you format the memory card first so that there is no trace of virus in the phone and remove any password from the memory card.

1. First of all make sure that your phone's battery is full and then switch off you mobile phone.
2. You'll need to hold three buttons together which are : The green button, left selection key and the no. 3 key
3. Keep on holding these three button and then press the power button to switch it on.
4. After this you'll get a screen which will say FORMATTING.... after that you can leave the keys.

Caution : This will completely format your phone memory and will reload the whole phone due to which you'll loose all your contacts or infact anything stored in the phone memory.

I hope this helps you....this step can be taken for any Nokia phone which has Symbian OS Series 60 Version 7 and above...you can say most of the phones which came after Nokia 6600 

please format your phone by dialing *#7370# and then entering your lock code.
remember it will delete your contacts,sms etc. also.

Not enough memory means your phone is too full of data IE. Pics, Themes, Contacts, Applications, Games, Old leftover files from sending via Bluetooth etc...
Do a clean up job. Get rid of all the trash.
The phone needs a certain amount of memory to function.

You can retrieve them only if you did a backup of your phone to your PC before you did a reset. If not they are gone for good. Not the ones on your SIM card they will still be there.

Hello there. Install PC Suite on your pc. Backup your contacts, sms etc.. from your pc. Be sure that you kept everything that you will need. When you are done switch off your phone. Then press and hold with the following order "3" "*" "answer button" "power on button" When you do this your phone will enter into a secret procedure which will format your phone memory and not the MMC. Your 6600 will be like a brand new and your MMC will keep it's data. If you wish to have an undo option make first a backup using Pc Suite. I hope this will helps you. Best regards.