Hello and Welcome to Free PC Help Jake.
I am not surprised by this behaviour as Windows Vista tries to create a thumbnail for every file present in the Window. This slows down the display process especially if the folder contains videos and music files. Fortunately, the feature can be turned off.
How to Turn Off and Disable Thumbnail Preview in Vista
Make the changes, save your settings and restart the computer. Does the window still take time to load?
-- Goku