I found a few similar questions - but couldn't find any exactly the same, so I apologize if this has already been asked.

I have a 2004 Blazer (no modifications, 6 month old battery). I am not currently driving it, so I have been starting it occasionally. I forgot for about 2 weeks... then when I tried to start it is was fully dead. I jump started it, and it started. I let it charge for a while (by letting it run), but it still will not start without me jumping it. Even after running it for 15 minutes, it didn't even have the power to allow me to use the automatic locks.

After doing this, I first noticed that my aftermarket stereo no longer works. Then I noticed that all the lights on my dash are flashing continuesly and the gas and temp. gauges are slightly moving back and forth. This stops as soon as I put my key in the ignition (without even turning it), but starts happening again when I remove the key.

Any ideas on what is going on? Let me know if you need more information. Thanks!