Car stereos are fused so check both fuse's.
If I remember, turn the stereo on, enter the code using the 6 preset buttons. After the beep, turn the stereo off. Then turn the stereo on and it should be OK. I just pulled my radio to get into the dash.
standby
The headlights turn off because you have accidently hooked the stereo's power wire onto the headlight relay wire. When you turn on the stereo, there's not enough power left to run the headlight relay. Thus, no headlights. Re-wire the stereo.
If it is an after market stereo, sound as if someone spliced the stereo power source wire (Hot Wire) into the wire going to the headlight switch.
the ACC wire from the stereo is connected to constant power (+12V)
since they both wont turn on, check to see if the fuse is burned out, a lot of times both the stereo and the controls for the heater are on the same fuse... if that is not it there could be a wire either broken or shorting out somewhere between the fuse box and the stereo/heater. also there is the possible coincidence that both the stereo and heater have quit at the same time... but I would check those things first.
The electric energy in a portable stereo is in the batteries. The batteries are what supplies the power to the stereo and in turn makes it work and produce the sound.
Behide the stereo
It is not the stereo. Behind the stereo there is a relay switch for the turn signals. It is going out and needs to be replaced. Autozone has the part about $30-$40
The speakers are powered by the stereo, which in turn the stereo has a fuse. If the stereo works (turns on), but not the speakers, then it may be a wiring issue.
In French, "stereo" is masculine. So you would use "un stereo" when referring to it.
On what exactly? if on a stereo or TV, turn it down, or turn down the bass/tremble.