Opening PK 3Files

Hello! Apologies for this stupid question, but I was trying to open a texture pack when I was very tired and made a huge mistake. I selected the option for windows to always open PK3 files with GZDoom. As a result I cannot play any of my mods properly anymore. Does anyone know of a solution to this problem? I need windows to stop trying to open PK3 files with GZDoom. Thank you in advance for any help with this.

Right-click on the file, and select "Open with...", and you can get other options there. As well as the ability to change the default program.

Also, a pk3 is actually a zip, so you can change the extension (even if Windows always complains about that)...