problem with DMX6 soundcard

i have just reformatted my harddrive,reinstalled xp,cubase vst5.1,yeah i know,stop laughing.I reinstalled my Terratec DMX6 soundcard,it took ages to install it,everytime i thought it was installed,i would look in device manager/hardware and it wasnt showing.
eventually,it did install and showed in device manager list.
but,when i plugged in the audio out on the back of my old pc i get a high pitched humming noise,sometimes when messing around with my kaos pad you dont hear it,then when doing nothing the noise returns.
I hooked up my midi gear and loaded the JX16 vsti that came with cubase ,i can trigger vstis ok but the sound is pretty distorted.
i noticed on some other forum folk having problems installing the DMX,i had to do it with the add new hardware wizard,i had to download the last drivers terratec have on their site as the DMX is no longer supported.
Does anyone have any ideas what is causing this high pitched noise and all the distortion when using cubase?
I had previousley plugged the DMX into my hifi amp in my living room as i dont have net access with the pc with cubase on it,got the same high pitched sound with that too.
My system is -
windows xp home edition
service pack 3
AMD Athlon 2600-1.91GHz

problem solved for the mo at least,changed config of DMX control panel.weird that it never made any noise like that before when i clicked on digital or mixed for playback.
now i can reinstall all my old song files,vsti’s and fx and my sample library.
guess you all use different cubase to my old vst these days,cant afford to upgrade and dont want to go thru another learning curve now i am pretty familiar with ye olde cubase vst!