Macbook freezes everytime I open the finder or use spotify! Really only happens when I scroll down past downloads folder, advice?

My Macbook 3.1 freezes eveytime I open the finder and scroll down to the downloads folder. I was attempting to clean out my mail downloads and all the stuff that seems to accumulate there so the folder is open. As soon as I go near it the whole things freezes up! The funny thing is that when I open the finder its fine so long as I stay clear of that folder or any of the items in it. Any advice? Am running 10.5.8 and would like to upgrade, that is why I was clearing files!