My speakers have been in storage for 3 months and now they dont seem to want to work. I was just wondering how you could tell if the amplifier was bad?

Why dont you try if you mean that you cant get any sound on your computer
control panel sounds and audio,volume you can adjust the volume or advanced,speakers select appropriate speakers or audio you will find 3 drop down lists make sure you have selected the right speakers or control panel,administrive tools,computer management,device manager scroll to sound,video and game cotrollers could be a yellow question mark? right click to re-install drivers
hope this helps