I switched off my phone and when i switched on after my meeting, i couldn't open my phone. It asked me; Enter restriction code:, and I have not put any code. Please help me to open my phone.

Restriction code is put by a network provider so that the user is not able to swap networks in the phone.I think your phone is locked with a particular network and when you try to insert other networks....it asks for the restriction code.I suggest you can approach Onlinegsmunlock.com and specify the country,locked network of Nokia 2610.Based on the availability you can get the unlock code along with free instructions.
http://www.onlinegsmunlock.com/nokia-2610/rs7wp9/

Restriction code and network unlock code is same..Nokia Phone asks restriction code..If your Nokia Locked to network and you are trying to inserting other GSM Network sim card it will display the message "Enter Restriction Code" Without unlocking it you cannot use other GSM Network sim card.After Unlock it you can use only gsm sim card...
You can get the Restriction code from service provider,but they ask to wait for many days or months.
So you can get the Restriction code for Nokia 6300 easily from the site
Mobile-unlocker.com/nokia-6300/rs2wp9/ and unlock it easily...To enter the code you can follow the instructions below:
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Nokia 6300 Unlocking Instructions :
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Warning : Do not enter any wrong unlock codes on your Nokia 6300 mobile phones. If you enter over a certain amount of wrong unlock codes on your Nokia 6300 mobile phone, your phone may get hard locked and sometimes become unusable.

1 - Switch on your Nokia 6300 without any sim card.
2 - Don't bother as to what is displayed on your Nokia 6300.
3 - Compose #pw+CODE+1#.
4 - The Nokia 6300 would then display the message "SIM Restriction Off" and will be unlocked!

Note :For Nokia 6300 mobile phones locked to the network Fido or Rogers in Canada follow these instructions :
1 - Switch on your Nokia 6300 without any sim card.
2 - Don't bother as to what is displayed on your Nokia 6300.
3 - Compose #pw+CODE+7#.
4 - The Nokia 6300 would then display the message "SIM Restriction Off" and will be unlocked!

The letter p appears if you press the button star(*) three times quickly
The letter w appears if you press the button star(*) four times quickly
The symbol + appears if you press the button star(*) two times quickly
The CODE you need to enter is the unique unlock code for your Nokia 6300

Your mobile is locked with network carrier..So whenever you insert a other network, your mobile asking the restriction code.you can get this code from Simpleunlocking.com .They will help you to unlock your mobile easily..

try code from service provider...............

You can get the restriction code from service provider...................

If you enter the wrong password for more then 5 times,it ll ask youu to enter the puk number....now call your customer care and get the
puk number...enter the puk number in the space given for password....thats it...problem is fixed
If you had locked your mobile then update the formware all saved passwords will be deleted.

normally pin code will be 1234 or 12345 if it does nt work pls turn off ur mobile and remove ur sim for 30 min after tht pls switch on ur mob it will be corrected normally

it ask me to put the restriction code

MY MP3 PLAYER REGSTATION CODE ASKING MY IME CODE IS-3570990008545
PLEASE TELE HIM REGISTRATION CODE

To enter the code to the phone (switch on without SIM card). Input the Code in the phone as follows:

#pw+??????????????+1#
#pw+??????????????+2#
#pw+??????????????+3#
#pw+??????????????+4#
#pw+??????????????+5#
#pw+??????????????+6#
#pw+??????????????+7#

Here: ?????????????? You should enter generated code.

_-_ first code in the end of the string must be added + 1#
_-_ code number 7 in the end of the string must be added + 7#

If You have proper software and You know on which lock, phone
is closed just simply enter proper CODE.

If YOU DONT KNOW - which lock is closed do the following:

1. Enter the first code, if it’s the wrong code - WAIT 30 seconds!!! And then:
2. Enter the code number seven this will open all locks.

How to get 'p' 'w' '+' signs?
Press * several times on keyboard of phone...

ATTENTION!!!
If the codes don’t work after entering 5 codes You will lock the ‘CODE UNLOCK FUNCTION’ and it will be possible to unlock the phone only by using a cable/device.

Here are your codes:
IMEI: 358648013665611
Network: 23430000

#pw+229125355703024+1#
#pw+123974050131176+2#
#pw+737950263501053+3#
#pw+143914670171415+4#
#pw+413317243165511+5#
#pw+893271725144273+6#
#pw+125874454360171+7#