connecting 5.1 speakers to desktop

Evening, I have a issue here.. concerning older peripherals. i have a gateway lx6810-1 running vista..

the jacks for the speakers i guess on the mother board..on the back of the computer

2 rows of 3 consisting of a purplish, black and yellow top row
pinkish, green and blu bottom row

speakers are altec lansing ada 995 one bass and 4 satellites

the 4 plug into the back of bass and off the base is a 3 cord wire w/ 3 plugs at the end a yellow, green and black

i tried different combos to plug them together and i only get the bass and 2 satellites at one given time....

so any help in getting this straight

thanks
ron

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft® Windows Vista™ Home Premium, Service Pack 2, 64 bit
Processor: Intel(R) Core(TM)2 Quad CPU Q8200 @ 2.33GHz, Intel64 Family 6 Model 23 Stepping 7
Processor Count: 4
RAM: 8190 Mb
Graphics Card: NVIDIA GeForce 8800 GTS, 320 Mb
Hard Drives: C: Total - 595471 MB, Free - 137161 MB; X: Total - 15005 MB, Free - 4675 MB;
Motherboard: Gateway, FMCP7AM
Antivirus: None