I’m using Audacity 2.1.3 and my OS is Windows 8.1 pro.The problem is that whenever I plug in my guitar processor pedal(zoom 707ii) into my PC for recording in Audacity I get a loud screeching sound in my headphone.All the instruments that I’m using are tested to be fine including the cables.What might be the problem??Please could anyone help??I would be really thankful 
.I obtained the software via the .exe installer. Thank you.
Check that “Software Playthrough” is off (not selected) near the bottom of the Transport menu.