SV1 Remote problems

Hi I have a SV1 box thats worked great for me for 2 years, with the odd updating here and there. I've recently been having remote control problems. I had this problem a year ago, so I bought a new remote control. Basically the remote freezes operations i.e the picture and sound is ok but cannot move up or down epg, or press any other buttons. Or sometimes pressing the epg button actually moves down a channel or list. I'm having to reboot the box 3 - 4 times a day. I also leave the lid open because I read from another thread that this helps. Its doesn't appear to be a remote control problem itself as now I have 2 remote controls that work. And neither works when remote operation freezes. Any suggestions?