I have a 2004 honda accord that was running fine, then I went to start it one day and the green key light on dash started flashing and car wont start now. does anyone have information or tips

no engine told , fuses (all) not checked. PCM not scanned for errors
cranks fast but will not start and run and stay running.!
right-o?
the car came new with 2 keys, lost both>? or lost 1 and now the other is dead, and the IMMO lamp on the days screams bad key bad key and not reading the glove box users guide (free ) to see how the lamp works, IMMO (thieft/security) >
i will now read page 81 in your guide to you. and linked

When you turn the ignition switch to ON (II), the Immobilizer System
indicator should come on for a few seconds, then go out.
If the indicator starts to blink, it means the system
does not recognize the coding of the key.
Turn the ignition switch to LOCK (0), remove the key, reinsert
it, and turn the switch to ON (II) again.

https://www.manualslib.com/manual/911114/Honda-2004-Accord.html?page=81&term=immo&selected=1#manual

USA dash cluster here, not told you, the country.
immo lamp is key icon, and must be happy or the engine cannot run.

anti theif problem. try un hooking battery for a few to reset computer

try changing the starter...

Timing belt ever been changed? Sure does sound like the problem. An old belt will snap on a cold start. Might want to look to see if the belt is tight and in place. These belts break regularly on Hondas with over 70,000 miles on them. Timing Belt change interval is 50,000.

Turn it over have someone spray carb cleaner into the intake, deos it start now, please let me know.

The green key light on the dash is your immobilizer system. If it flashes at you while you are cranking (no start). This means the key that you are using is not programmed to the immobi control unit. Try using another key. if all other keys are lost you'll have to get it down to you local honda dealer. it takes a special honda scan tool to program these keys to the control unit. If you don't want to spend money on a tow truck, ask you dealer about the Brake Code. This is a code specific to each vehicle. If your keys are lost/stolen you can input this Brake Code into the control unit by using your e-brake (special procedure). this will give you 10 free starts to get it to your dealer. (limp-in mode).
-hope this helps

sticking valves. the short run of the engine free's them enough to enable runnig

The Green key Flashing indicates an issue with the immobilizer of the vehicle. This could be a problem with the key being not programmed, or having lost its program. Or this could be an issue with the immobilzer unit, or the part of the ignition switch which reads the key. If the vehicle is cranking with the green light flashing, you will ultimately need the honda dealer computer to program either the key or immobilizer unit.

first of all recharge the battery

the altornator might have got out