Like I have already mentioned, run svscmd /? from the command line to get the switches.
You first need to deactivate the layer which will basically be the same as uninstalling and then delete the layer to remove the layer from the machine if you so wish.
There will be a deactivate switch as well as a delete switch. The help will also provide example syntaxes too from what I can remember.
I think it will be somethin like:- svscmd.exe "layername" /deactivate
However, it could require the layer guid instead or have the switch before the layer, so please use the /? switch to get the help information.