No Sound On Macox 10.3

Hi folks i was wondering if someone can assist me with this problem. I have an Imac and it was running MACOS 9.1 everything was fine until added a 256 PC100 U memory stick and i did a clear installation of MACOS X PANTHERA. Now i don't receive any sound, when i go to System Prefferences and i click on sound it shows that there is no Input/Output sound. The sound is not on mute just letting you guys know. And i don't think it's a hardware problem because when i was running macos 9.1 sound was fine.

are these usb speakers were talking about? if so, unplug them and shut down your mac for about a few minutes, then start it up, then plug them back in. if this dosent work, try
repairing permissions. if that doesnt work, take out that ram you added and see if the speakers work then. what brand is the ram, and whered you get it?