Speaker work, but no sound from integrated motherboard

I bought a Dell Dimension 4500 in 2003. As life would have it, eventually it got bogged down and I had to wipe everything out and reinstall the entire system. I have everything running except (and there's always an exception...) the sound. I have integrated audio connections protruding from the back of my motherboard. I can't (I mean I have searched to the ends of internetdom looking for) find the drives. Can and one link me up with them?

I'm not sure what all to tell you about my computer, so here goes my best shot: Running Windows XP Home version, Processor: 2.40 gigahertz Intel Pentium 4 8 kilobyte primary memory cache 512 kilobyte secondary memory cache Not hyper-threaded Main Circuit Board: Intel Corporation D845EPT2 AAA83422-107 9 Bus Clock: 133 megahertz BIOS: Intel Corp. A03 07/18/2002 Controllers: Standard floppy disk controller Primary IDE Channel [Controller] Secondary IDE Channel [Controller] Standard Dual Channel PCI IDE Controller Displays: NVIDIA GeForce4 Ti 4200 [Display adapter] NEC AccuSync 95F [Monitor] (18.0"vis, s/n 0Y50164YA, October 2000) Bus Adapters: Intel(R) 82801DB/DBM USB 2.0 Enhanced Host Controller - 24CD Standard Universal PCI to USB Host Controller (3x) Mutlimedia: None (this is where I need someone's help!)