remote keyless problems

Hi everyone, I just bought a 2008 mustang and it came with only 1 key and keyfob so i purchased a second set. After I had the car a few days the remote quit working so I figured it was a dead battery or lost the program somehow. I got the original keyfob and it wasn't working either. After driving around a little bit they started working again. We took a little road trip Friday and Saturday and when we got home Saturday afternoon, the same thing has happened again. Nothing works, doors, and trunk are all out. Sometimes if i keep messing with them they will work but only intermittantly. I'm hoping its just a loose connection somewhere. Does anyone have any ideas? Thanks in advance.

Thanks for the responce sparta. I kinda thought it might be a programming issue at first but then they both started working fine. We took a 500 mile round trip over the weekend and never had any other problems with it untill i pulled back in at the house. Both times it stopped working was at the house. I got to thinking now, I park it next to my 01 powerstroke and it has remote door locks also. I wonder if that could be causing any problems? I also have a couple of wireless security cameras out there, there again radio frequencies. I shut down the cameras and will see if it messes up any more. As a sidenote, this morning i went out and tried the remote and its working fine... used it several times today and everything is great.