2002 Honda CRV. radio CD - CODE

I own a 2002 Honda CRV. I bought it used and all owners manual was provided with the purchase. I lost power to the car's system and the radio set itself in an anti-theft mode requiring a code to get the radio to function again. I tried pushing several buttons without succees.
I need your help to put the right code!!

If an audio unit with theft protection is disconnected from electrical power, you must enter a unique code number into the unit or it will not work. This code and the audio unit’s serial number are listed on the anti-theft ID card that comes with the vehicle. If this card is lost, you must obtain the audio unit serial number in order to get the radio code (some people say that they have found the code on a sticker inside the glove compartment, but I wouldn’t count on that). Some newer vehicles allow you to retrieve the audio unit serial number electronically from the radio. Refer to your owner’s manual for the specific procedure (the following usually will work: Turn the radio off. Push the preset 1, preset 6, and power buttons at the same time, then quickly release.)
. Some older vehicles (model year 2003 and older) require a visit to the dealer in order to retrieve the audio unit serial number. Once you have the audio unit serial number, you can call Auto Customer Service at (800) 999-1009 or have the dealer look up the radio code.
Hope this information will help you get started on the process.