Ok guys, there are quite a few of us it seems that don't want to go to the dealer to have codes cleared/read from our cars. I felt the same and my airbag light was on after a seat swap so took a gamble at buying a 'INPA USB OBD2 Interface' from Ebay, I didn't hold out much hope but after having looked at it today it seems it might do the job fine.
The CD included install instructions which I followed, I then went out to the car to try it out, no joy and all I could get was this error, I wasn't too surprised as my laptop has a real serial port on it and this was a USB device. All the documentation refered to using COM1 which Windows always wants to assign to the real serial port.
After some digging around I checked device manager (open windows explorer, right click 'My computer' and choose 'Manage') in the left hand pane click 'Device Manager' and then in the right pane expand the 'Ports' entry, mine looked like this
I then edited the following file C:\EDIABAS\Bin\obd.ini and changed the second line to match what was specified in device manager for my USB Serial Port (com6) like this, exit and choose to save
The software could then talk to the car fine, the ignition key needs to be turned to the first position. My airbag light was on so I'll show you what I did to diagnose and 'try' and clear it
Start the software and press the function key relating to your model (mine is E46 so press F3)
We are interested in the Airbag system so choose 'Body' and then 'Airbag' you can use you arrow keys, TAB and Enter here or just use the mouse to click/doubleclick. The other modules, engine diagnostics, ABS etc etc follow a similar procedure to read/clear
Now we are into the airbag section and can interogate the module, press F4
Press F1 to read the stored code
Press F2 to clear it and wait for a confirmation
Now press F10 until you exit the module and the program itself, turn the ignition off, remove the cable and you are done.
This procedure didn't clear my error as the more astute among you will have noticed that the seat occupancy sensor is at fault so a bit more work is required to sort it.
Hopefully someone will find this useful when trying to decide on what software/device will suit them. Now if someone has guide for using NCS-Expert then I'd be very interested to see it. If anyone needs anymore info or wants to see anything else then please let me know.