CS3 was a bugfest that often did not work properly and in my experience so far CS4 Bridge has its own set of problems. In my case it will not retain file associations, failing to recognize things like "nef" files although Windows sees that file type as associated with CS4. Resetting the association works for a while but then it is mysteriously lost again. CS3 Bridge would NEVER open jpegs in the converter automatically no matter how preferences were set or reset. Unfortunately Adobe has the copy protection mentality of Microsoft and the support mentality of Apple. You may need to deactivate CS4 and run the uninstall routine. Then manually comb the register for references to CS4 and delete these. Reboot, reinstall. Hope that helps.