If you have a large media collection - music, video, or photos - be sure to place them on a fast hard drive, if possible. Most media players and browsers will create a catalog of your media files and accessing that catalog can take a lot of time - and slow your PC down - when the media player starts.
An alternative to cataloging a large media collection is to force your media player not to catalog all of the files. Instead, open the music or video files individually.