guess i spoke too soon, the audio crackling thru presonus firestudio project started again, just like before, almost constant crackling! I switched realtek onboard audio in bios on, now the audio is better thru presonus audio card.
I've been borrowing friend's M-Audio 1010LT card for couple last days, because I had to really finish some projects. It was working perfectly, than I got response from PreSonus how to reinstall firestudio project with additional registry deleting procedures, now firestudio project works fine..
I think the combination of all these (realtek driver dwnld, codec pack donload, 1010lt install and unistall, and presonus procedure) made this work.