I suspect it was not connected to your cars power source that always has power from the battery. If your cars stereo was connected to the wrong side of a fuse (fuse box) it louses all electrical power when the car is shut off. If your engine is off, you lose all power COMPLETELY and your radio needs a little power from the cars battery to hold the programing. The radio hot or positive (RED) wire is incorrectly hooked up. I'm not a radio tech. but try this. Find the fuse box usually located under the dashboard. Every fuse has 2 pins. Remove a common fuse such as headlights. Where the fuse plugs in there are 2 fuse holders. One of those fuse holders is a continous power source, the other holder would supply power to your radio ONLY WHEN YOUR HEADLIGHTS WERE TURNED ON. Being very careful, make sure your headlight switch was OFF position. Try touching the radio RED wire, only one at a time to each of those fuse holders. Be careful not to touch red wire to both at same time. That could short out and damage your radio. One of those 2 fuse holders should provide enough power for your radios pre-sets. Test with the radio on as well. You don't want a connection that will play your radio with the key in off position. Your likely to forget to turn off the radio and it would drain the battery. You want the connection where the radio goes off when the key is removed but doe not loose the pre-set power. It will take some testing to see what works. Every thing on the radio should go off and radio appear to be turned off but provide small amount of power to your pre sets. Don't forget to put your fuse back in so you have lights. Good luck..
