Lost sound with new monitor

[Has beens]

Ok,
I bought a new monitor with internal speakers ( previous one did not ) and after hooking it up and loading the set-up disc, everything is great except for sound. I tried unplugging the wire and plugging my desk top speakers back in and no sound from them either.

Help !!

thanks in advance, I am a baby with computor issues !

 

[mexikaz]

if u are using WINDOWS

go to start
then right click my computer
left click properties
click on device manager
then check if u see any yellow question marks on that list ur looking at

let me know if yes or no

 

[Has beens]

All the system checks out fine. I started plugging and unplugging the speaker cable into different jacks in the back of my computer and I can get it to work if it is plugged into the sub-woofer hole. On start up, my monitor screen also displays a small "d-sub" box briefly at start-up.