Certainly not a General Hardware issue. Anyway, two ways to do it. One, hold down the shift key while you right-click one of them, and select Open With, and select the program you actually want them to open with if you always do want them to be the same program. You can use that to open them with something else on those occasions you don't want the default.
Two, open up a Windows Explorer window, Tools, Folder Options, File Types tab. Find the extension, click the Advanced button, and delete all the action options, or hit Set Default if you want to see what it changes them to. Alternately, you could just delete that file type from the extension list and that'll completely remove any options.