How can I fix my Kenwood KRC-794?

I have a Kenwood KRC-794 fitted in my car. I recently had to change the battery and the stereo hasn't worked ever since. At first, the stereo would light up when i clipped the front on but would not respond (think it needed recoding - don't have the codes). Then, after playing around with it I must have held down the off button because it has switched off, the front has hidden itself and I can no longer get it to swivel round so i can remove the front or press any buttons. There is a transmitter on my key fob which does not seem to work - have tried changing the battery.

Any ideas?

Don't really want to spend much money on the stereo as it came with the car which cost very little. Thinking i might just cut my losses and replace the stereo with a new head unit.