I have a Honda Civic coupe LX 2006, a friend of mine left its headlight on for 10 hrs and now when i try to start, it won't start. i tried almost everything but still unable to resolve the problem. i went to repair shop and they said there might be problem with key since on my dashboard the key sign light is blinking and doesnot stop. however key is working fine, i mean the remote. did anyone had similar experience in past?? need help!!!

My first guess is your battery died due to excessive length of time it turned on without running engine (assumed). Ask someone else nearby to lend you a jumper cable and car to start up. good luck.

 try Jump the car http://uk.answers.yahoo.com/question/index?qid=20100819063025AAPnNdr

Thanks guyz, but i already tried jump start the car. it didn't work. it cranks as if it's about to start but dies eventually. Do you guyz think it has something to do with security system? coz i was told by a mechanic that it could be security issue and should take it to dealer.

change the battery. don't listen to the mechanic.

 Try this :
 
Have the car that you getting jump from have its engine turned on (start garnush) for about 5 mins and have your batarries hooked up at the same time and after  5 mins start jumping and make sure when you jump you give gas on the first car from time to time. 

turn off all the things like headlight/ a/c etc and jumpstart your car running your engine for a while.. it should work i guess as per my experience

 C'mon guys, it is a 2006 model. Battery doesn't die due to leaving the light on coz it is equipped with automatic light turn on/off sensor.
Try to look on the manual what the sign indicates, and you will know the problem. It might be anything from battery, security, alternator, anything...

 no offense but from my numerous experiences Furke is always trying to get smart ass. DO not other Sajha guys feel the same way. Again , I am sorry this is just how I feel when I look at your posts. 

 To my best understanding, your vehicle has been immobilized probably due to complete power shut off (battery drained). It is a security issue to prevent thieves from not letting use the car. Take it to the dealer. 

 [Disallowed String for - Bad word 'fuk'] you Bire,
Don't try to get into other's asshole. Just look after yourself.

Mushromhead,
"i went to repair shop and they said there might be problem with key since on my dashboard the key sign light is blinking and doesnot stop. however key is working fine, i mean the remote"

You went to repair shop by yourself and explain the situation right. But you did not towed your car to repair shop right. If you have already towed your car to mecahnic and mechanic is just assuming this and that might be problem then let him do trouble shooting. he will come up with solution.

If you have not towed yet. and also you said you try every thing But we dont know what you tried. Please let us know what you tried.

"a friend of mine left its headlight on for 10 hrs" seems like this is the show topper.

As dekchi said try honking. does it honks loud or weak ? or you can turn your head light. will it turn on? if it turns on how bright it is or does it go dim when you crank while head light is on ? what sound you hear during cranking ? do you hear click sound? Have you check cable which is attached to battery ? is it loosly connected ?

more likely it is battery problem.
if not then may be cable which is connected from battery to starter.
if not cable then may be key area where you insert key and crank it. it may not be connecting properly so it is not cranking.
if every thing is functional mentioned above then you can check FUSE also some time this tiny things give problem and we overlook it.( i dont know ow to check it though)
Then may be there can be problem with starter( if you hear click sound but car wont start)
There can be alternator problem if car starts ( by jump start ) but cannot charge battery.

Solutions:
If it is a battery problem then try jump starting ( check proper way to do it. search in google you will see lot of video regarding this)
if jump start doesnot fix this then change another battery and try it.
If battery is not problem then my friend you have to tow your car to mechanis and they will take care of it.

Mushroomhead,
If mechanics is telling you to take it to a dealer as he cannot fix it then take it to a dealer. DO you think sajha users are more experiences than that mechanics.
If i were you i would have already taken that car to dealer and fix the issues.

Thanks sulab and other friends for suggestions, but i think i got to take it to the dealers now coz i believe due immobilizer system, somehow the car is not recognizing the key. the owner manual says the same thing. I didn't had owners manual before but now i found it through google. The manual says- "When you turn the ignition switch to the ON (II) position, the immobilizer system indicator should come on briefly, then go off. If the indicator starts to blink, it means the system does not recognize the coding of the key. Turn the ignition switch to the LOCK (0) position, remove the key, reinsert it, and turn the ignition switch to the ON (II) position again.  The system may not recognize your key’s coding if another immobilizer key or other metal object (i.e. key fob) is near the ignition switch when you insert the key. If the system repeatedly does not recognize the coding of your key, contact your dealer."
So i think there is no other way to solve this problem if i don't take to dealer. Anyways, thank you all for your suggestions.

Hmm,
keeping headlight on for 10 hours screwed up ur key? that doesnt make sense...you might have already tried your spare keys,
for me, when the battery drained, the dashbaord lights started flashing when i insert my key, i thought some aliens invaded or something.., anyway take it to the dealer, they should have all the solution..

Usually the factory installed batteries require replacement after 4 years. So, I expect weaker performance of your 2006 model car. On top of that, after leaving headlight on for 10 hrs, I have very less hope on the life of your battery.


Did you charge the battery enough long while trying jump-start? I had similar experience. I failed to jump start my car. Then, a usps postman saw us struggling to start my car. He suggested us not to try kick-start too soon. after connecting the jump wire. Sometime, they don't supply enough power, because they are designed to supply recharging power to nearly fully-charged batteries. The better way is to continue battery-charge for 20 minute before trying kick-start (that means continue running the second car connecting the jump-wire and occasionally press gas. An engine running in idling mode won't actually supply enough power). At the time of recharging the dead battery, take out key from your troubled car. Once the battery gets enough juice, it may reset the immobilization system, making it ready to recognize your key. Then, when you are ready to kick-start, run the engine of second car high, so it continue supplying power, in addition to the battery you have. If your immobilization indicator is still blinking, then, do not try kick-start. Give enough time to see if the immobilization system resets. You may try this before calling a tow-truck.

Last week my car ( Honda Accord EX 2002 )did not start, when I start, there was a click sound but did not start. I doubted the battery and changed in from auto zone, it started immediately but gave the same problem ( did not start next time). I called a mechanic and he doubted several things but his prime suspect was starter. He replaced it and now its fine ( starts and runs great). you better try changing it . Hope it works.

 hey i had the same problem with mine with same model except mine was EX. had to freakin tow it to dealership i was so mad. had paid decent money for it..

the problem with mine is the fuse box went out. Had to pay honda 200+ for diagnosis. There you go atleast i saved you the diagnostic fee

make sure you change the battery right after the problem is resolved.. Tire plus had warned me before the battery was getting weak, i just ignored them, turned out later that because my battery was weak, it had blown the fuse box...

I had exactly the same problem man, it would crank but wouldnt start, even tried jump start no luck. I am sure it is the same problem with yours.. Lemme know..