You could try looking in Device Manager.
My Computer / System Properties / Hardware / Device Manager
There's an option under the View menu to view Devices by Connection (its not the default view, you have to select it)
you can then scroll down looking for Communications Port COM 1 which will have a + by it if anything's connected, click on the + to expand the tree.
Also if you double-click on COM 1 to bring up its Properties box, there's a Resources tab which should show device conflicts if any. Not an infallible guide, in my experience.