System Sounds - if you're in KDE, go into Configuration - KDE - Look n Feel - System Notifications and sort out what you want there.
Flash - yep, download the plugin at - http://ruslug.rutgers.edu/macromedia/site_ru.html
Get the Mandrake 9.1 version. Choose - Save As. Then once downloaded, click on the file in a file manager. It will ask for the root password, then it will install. Then, restart your browser and scan for plugins, if you need to. Then try a Flash-Enabled site.