Sorry if this has been asked before, but I can't find anything on searching the forum. When I try to download a .dmg file, say ONYX or Safari 4 beta, the main windows of Safari and Firefox go grey and nothing seems to happen - the download manager box stays empty. I don't have any trouble in downloading the updates from apple via software updates. E-mail works fine. I have recently updated my router to a new Apple Extreme base station and the modem has been reliable for year; both seem to be working well. I've presumably got some setting to change on my iMac but for the life of me I can't work out where. Running Leopard on a new iMac 4Gb 24", all software up to date as of last night. Any help would be gratefully accepted.