Well hello there, and welcome to LQ
You will want to look into what soundcard you've actuall got, ac97 is generic audio codec, not the soundcard. As root use:
To look at your soundcard. Look for multimedia controller and post it up if you have questions. Then, either try modprobing for the module for your soundcard (which a search on google.com/linux or www.alsa-project.org
might show you) or rebuild your kernel/add alsa for support. Then, you will need to either chmod the /dev/dsp /dev/mixer to allow users to use it, or add your users to a group who will own and have rights to the audio devices (this can also be found from a search on this site, it's a common question on new slack install
Your internet is a bit different. THe DLINK gateway is fine, however you will need to configure your NIC/Ethernet card first (well probe the module for it anyway). Find out what it is from the lspci -v also. If you have questions on it, post up the results here.