To change how Firefox handles downloads, you can adjust a setting in Options, on the General panel. Instead of setting a specific folder to be used every time, try selecting "Always ask me where to save files." This article has the steps: [[Startup, home page and download settings]]. Was that what you meant, or was it a different problem? By the way, when you select Open in Firefox's Open / Save / Cancel dialog, the file actually is downloaded to the Windows TEMP folder.