Toyota Matrix Stereo not workling!

[50 cool 50]

Hi we had the battery disconnected in my wifes '04 matrix for a few weeks.
It now just shows a blank screen and does not power up.
If you hold one of the buttons the clock comes on showing the time but that is it :0(
It is model number ADI800 written on the stereo
any ideas to get it working would be great to save pulling it out and replacing it

[fishexpo101]

Have you tried loading a CD, does it do anything? Do you know if it is one of the OEM anti-theft variants?

Try a quick power cycle, disconnect the negative battery terminal for a minute, reconnect it and see if the headunit powers itself on once power is restored. If there any error messages, they will be displayed now. If there is a CD in the unit, it will cycle the CD out immediately after it is power cycled.

Also couldn't hurt to double check the fuses, sometimes you don't get a completely blown fuse and it will electronics act intermittently.

It if still ends up "dead" - then you are probably looking at just replacing it. Could be something pretty simple with headunit, but even simple repairs to something like this would cost more than just buying another one.