Delay in Files Opening in Finder Window

I have a Mac Pro tower with Snow Leopard, and there is a long delay, sometimes 5-6 seconds long, before files open up after being clicked on within the Finder window. The delay happens with any file, such as a MS Word file, .jpg file, .pdf file, whatever. The result is always the same - a long delay before the file opens. It doesn't seem to matter if the file is large in size or not. Before the Mac Pro I had a G5 and it opened files much faster than this brand new Mac Pro.

Is there a fix for this problem?
Thanks for any tips.

Perhaps a bit of troubleshooting. Quit all other apps and see if it changes. Go into another User and see if it happens there. Get out Onxy and do a bit of housekeeping.