Last year I ran my computer off a power inverter and powered my XM reciever from the cigarette outlet. Everything worked fine. Now this year, I got a new laptop and I can't get XM to work when I have power going to my computer in the car. The people at XM sent me an AC power cord for my reciever so that I could plug it into the power inverter. Everything works fine when I use XM in my house, but when I tried to use it in the car I get a COM 4 error(COM ports are matched up though) or when I start it up it won't recognize the radio serial number even when I use the AC cord. If I don't run power to my computer and only plug the reciever into the inverter, everything works fine. I went and bought a second power inverter (300 watts) and figured that running the reciever and the computer on seperate power inverters would solve the problem. It didn't though. I don't know if my new computer is just a power hog or what. I remember reading a thread a while back about getting more power from your alternater(spelling?), but I can't find it now. I tried it in my dad's truck and had the same problem. Shouldn't my car be able to power a computer and my reciever? I would think that it has to be a power supply problem. Any advice on how to fix the problem would be greatly appreciated.