I'm not sure if I'm on the right lines with this, but I suspect the /original/ DVD drive may be set to play a disc automatically. Does that make sense?
If so, suggest you try the following:
a) Right-click over the /original/ DVD drive icon in My computer and select Properties.
b) Select the AutoPlay tab and select either <Take no action> or (if you want the contents folder to open automatically) select the <Open folder to view files> option.
c) Click on Apply and OK.
Then if you put a disc in the drive, either nothing will happen or the contents directory will open automatically (your choice). HTH.