Stereo problem

[flamingheads]

A few days ago I started up my car and turned on the radio. After about 10 seconds it started flashing saying "PROTECT" and does it every time I turn it on.
I can't think of anything I could have done to make it do this. Any ideas what the problem could be or how I can stop it?

[shortround]

Is it the factory head unit?

Had a flat battery?

[flamingheads]

It's an aftermarket stereo that I got with the car. The car has an imobiliser so the stereo is hooked directly to the battery so it doesn't lose its settings every time I turn the car off.
There haven't been any problems with it in the couple of months I've had it then this seemed to happen out of nowhere.
EDIT: No flat battery.

[Damoss]

Obviously this is an old thread but for anybody else who has this problem; "PROTECT" error usually comes up when there is a short to ground in the speaker wiring (usually terminals on back of speakers or wires through door).

[lolwat]

LOL