I recently purchased a netbook running Win 7 and then an external DVD player which was plug & play, a short time after plugging it in the usb socket a message appeared saying "Drivers installed and now ready for use" so just where are the drivers installed to and can they be deleted if needed ?
Drivers would normally be installed in C:\Windows\system\drivers or C:\Windows\system32\drivers if you have a 64-bit version of Windows.
They can usually be deleted exactly like you would delete any other file, so long as the device which they drive has been unplugged and uninstalled, and you have permission on the folder where they are stored.
You shouldn't need to to this, though - it will make no difference to the operation of the machine.
Thanks for your answer MarkRae, the reason I asked this is because I have now seen another DVD player/writer (still usb plug & play) but a different make and model which I think I would prefer however a friend of mine did exactly that on her netbook and had no end of trouble with it and was told it was because one set of drivers was conflicting with the other and she should have deleted the first set of drivers before plugging in the new external DVD which has now worried me about having the same problem.
They'd almost certainly use the same driver anyhow....
If it does cause a problem it would only need to be removed via device manager which you could do either by plugging the old drive in and then uninstalling it through device manager, or if you've not got the drive to hand you can make the device manager show non present devices and then remove it.
if it does cause a problem at the time post a question about it and somebody will tell you how to remove it.