350Z Not Starting After Suspicious Alarm (Possibly?) Not Allowing It To Turn On.

So I left to go back home a few days ago, and that morning I had my friend with me to go to the airport so he could drive the car back. I have gotten back recently and the alarm system is on, but the remote start seems to have lost connection or something. The alarm system I have is an old Clifford model that has been discontinued (as I have checked). My friend said the only time he drove it was to take it back to my house where it stayed dormant for about five days. So when I came back, he said he locked it, which is something I never usually do when I'm in my neighborhood (because it is fairly safe). The remotes battery died in the midst of my car being locked, and now I can't turn the car on even after I changed out the battery in the remote. The remote clearly works now, but I have no clue as to why its not connecting to the car. Do these two variables happen to relate at all? Do I have to reset the alarm to be able to start the car back up?