My new ( to me) A8

Well folks, I went and did it, got myself a 2007 Audi A8 3.0 tdi,
I love it, but it's giving me a few problems already, not even have the car a week but no warranty with this one as I got it cheap in the first place, first of all the central locking is Messing about, I can walk up to the vehicle and the passenger -side recognises my key and will open the doors not a problem ,don't even need to press the key fob, but the driver-side ,well that's a different matter, it just will not open unless I unlock it manually ,that's both the front and back driver-side door, als soon as I go near the handle the indicators to start flashing, I can hear things we are in the me wearing them buzzing away but nothing happens,
It's just had a new battery in the car, and also a new battery in the key fob so I know they're all okay, I've tried to do this research program thing that I've read about online were you put the key in the ignition after Opening the car manual it and it resets everything, but that's not worked either, any of you guys had similar problems and how did you fix it please please please help

well the plot thickens! iv done a scan, and so has the bloke I use at the vw audi garage, vagcom came up with the following
code-02115 implausible signal intermittent , fault stat 00101000
and also -code 02126 cent lock ext door button implausible signal intermittent
but now my window wont go up???
it works ok when I do a output test to test the motor, and closes fine with that, just not if I use the switch
could all this be down to water getting in, or a dodgy connection or something,
I have just replaced the car battery as well, could that have something to do with it?????
also when I look on the net for parts for the central locking , I just keep getting parts for the A6? , are the parts the same or something???
please help,

oh, the car locks just fine with the key fob, I just cant open the driverside doors, the driver door opens ok with the key, but not the back door?

real problem now???
after fitting the new mmi gear (with the battery disconnected) , I fitted my nice shiny new 19ince alloys, everything was looking well, took the car out for a spin, only out for 10 mins, just up the road and back, just about to put the car back on the drive and BANG! the thing just stopped?
all sorts of messages popt op on the DIS, e.g. low oil pressure, abs fault, parking brake fault, esp fault, headlight range fault, so on and so on,
the ****** thing just wouldn't start again and me and 2 blokes had to push it back onto the drive, iv run vagcom through it but I got messages saying module not found for almost everything?
NOW IM REALY STUCK!!
iv only had this motor a week and up to now, iv had nothing but problems,
could all this be down to the battery, the guy at the garage I bought it from put me a new 1 on the car, but I kept getting a message while trying vagcom that the battery was low?
also, when I disconnected the battery again, to se if it would rest anything, the car started fine, ran for about 30-60 seconds then just stopped, all the messages popped back up?
I am very confused now, and have no idea of what to do, any help would be great

No I meant it as a metaphor, just stopped and that was that, I think it may be something to do with the ECU, I'll phone the dealer I got it from and he is sent into a place to have it diagnosed and see what's what,

If it is the ECU what kind of money are we talking about from Audi, I have seen places on the Internet that do refurbished EC use as in you take your old one off and post it to them and they send you out a new one and that's about 2 1/2 to £300, the thing is the place that he sent it to deals with Mercedes ha ha

Cheers, I'll have a look with vagcom as soon as I get the car back, it's been a week they have had it now, I'v phoned the garage where the repair is being done, and the bloke on the phone told me he hadnt had chance to look at it yet, he did seem very genuine and okay though and did apologise and told me there was very very busy at the moment, he said that someone will try and get onto it on Saturday afternoon, and to form back on Monday and they should know more,
I think it's the ECU that's gone duff, and so does my local vag specialist,
Even the guy from green flag said it's only like the Ecu,
Just hope they sort the ****** thing out, when I get it back soon as because I need the thing, it will be nice to be able to drive it again, after all I have paid for it