Go out to Google Images and search for "IDE CONNECTOR" and see if you can locate pictures of what the two different connectors look like.
The 5.25/3.5" drive IDE connectors will have a 'key', by the way, - usually a plastic 'slot' that means a connector has a "top" and "bottom".
The other different type of connector is for notebook drives - 2.5" IDE drives, and these are smaller and have the Power Connector plug (4 pins) stacked on one edge in that narrower IDE cable.
If you can post pictures of your IDE connectors, maybe we can give a more specific answer. (In the toolbar of the REPLY message-box, there's a yellow tool with Mountains & Moon in it - that's the "insert pix" hyperlink tool.)