My car stereo. I brought a new kenwood Kenwood KDC-237SA CD Player for my nissan almera last week.

Question

I brought a new kenwood Kenwood KDC-237SA CD Player for my nissan almera last week. I was able to remove the old stereo no problem. Connected up the my new stereo and when I went to turn it on the lights on the stereo flashed then went off. I automatically assumed that the new stereo was at fault so jumped the gun slightly and got on the phone to the supplier and had a right go. Long story short, removed the new stereo and fitted the original stereo only to find that the old stereo also stopped working. I assume that something with the internal wiring has gone wrong somewhere.where do I begin checking to try and find a fault?