Hi everyone, I'm looking for some help finding where to start to deal with a multitude of issues with a 2004 C5 exclusive 2.0 Hdi estate. I bought the car privately 2 weeks ago, the seller told me there was an issue with the battery draining but it didn't seem to be too much of a problem. I drove it home an was very impressed, the car drove perfectly and performed well with no glitches for the rest of the day. Once I had finished with it for the day I parked it up and disconnected the battery. The following morning I reconnected the battery went to start it the first thing that happened was the engine turned over fine but would not start then a warning came on that the tailgate was open.I checked it and it wasn't so I tried to start it again, engine turned over fine but wouldn't start then a warning saying engine immobilzer fault came on. I got out of the car tried to lock it but the plip did not work so I locked and then unlocked the car with the key tried to start it again and it fired up first time.Again the rest of the day it was fine so I disconnected the battery again and the following morning I reconnected it, tried to start it, tailgate open warning followed by engine immobilizer fault warning locked and unlocked with the key tried again and started fine. Happily driving to work suddenly another warning saying anti pollution fault followed by EGR/ASR (I think) warning) followed by engine management light, followed with big red STOP on the dash. The final thing was loss of power followed by engine cutting out. It flatly refused to start again so I had it trailered home where it is a driveway ornament. I am reluctant to give up on it as it is such a lovely car. HELP. There are other minor niggles that I haven't gone into yet as this is rapidly becoming a novel rather than a post.