Try updating Firefox to version 11, Firefox 3.6.28 is going to be dropped from support in just a few weeks, and will not longer be receiving security or stability updates. Also, Firefox 11 is up to 7 times faster than Firefox 3.6, offers lots of new features and improvements, as well as reduced memory usage and new web standards support. Second, check Windows for all updates, update your adobe Flash, [http://fpdownload.macromedia.com/pub/flashplayer/current/licensing/win/install_flash_player_11_plugin_32bit.exe http://fpdownload.macromedia.com/pub/flashplayer/current/licensing/win/install_flash_player_11_plugin_32bit.exe], update your graphics driver [https://support.mozilla.org/en-US/kb/how-do-i-upgrade-my-graphics-drivers https://support.mozilla.org/en-US/kb/how-do-i-upgrade-my-graphics-drivers] and read [[Basic Troubleshooting|Basic Troubleshooting]]. Now, as for your download helper dropping in download speeds, have you tried pulling the power from the back of your modem and/or router? Try doing that, leave them unplugged for about 5 minutes, restart your computer, plug the power back in, then try reconnecting. See if that helps your download speeds. Have you noticed if anything else on the internet has slowed down also (youtube videos take longer to buffer, etc.)? That may be a sign you need to contact your ISP to have them diagnose your lines.

Thanks I will try all your suggestions, if you don't see another comment that means everything works.