Squealing or squeaking at engine startup

I have had squeaking and squealing going on for a while and I changed my serpentine belt about 3 months ago and it didn't stop. I just last night changed the serpentine belt again along with the belt tensioner assembly as well as the idler pulley and I'm still getting the squealing sound every time I start up my van. It does stop after a minute or two but it's still doing it nonetheless. Please help with any ideas or suggestions that you can give or offer.