Honda Accord won't turn off?!?

[Jacob G]

My sister has been driving a 1997 Honda Accord SE for about a year. It was always driving fine until suddenly the check engine light came on. While the engine light was on, the D4 light was blinking and wouldn't stop blinking even in any other gear. Today after taking her to work the car wouldn't even turn off. I took the key out and it was still on and was still able to drive it without the key! So I had to take the battery off.
Can this be a computer/electrical problem? thanks!
Would this be caused by going over speed bumps quickly or by water splashing up under the car?
It may be the alarm. Because it has randomly been going off!

 

[Matt]

Taking the battery cables off wouldn't have caused it to stop unless you unhooked the alternator as well.

 

[Nicole]

The lock cylinder may need to be replaced.

 

[matthew.allender]

I had this same issue with a 2005 Jeep Grand Cherokee. It was brand new, only 3 months old when this happened. I took it back into the dealership and they tried to blame it on an alarm that they installed. almost cost me my warranty, because they said i had installed aftermarket equipment. not an answer but i just needed to vent after i read your question. i sold the jeep quick btw.