? Strange?
when you open up your project, before pressing play or anything....can you not render each trk from start to finish and load them all back into a fresh page?
Its a ball ache i know,...ive had problems like that in the past myself but not with the soundcard......thats the only way ive managed to salvage any projects that have froze-crashed.......only happened a couple of times though, usually stable as.
other than that mate,i dont know?
hope you get it sorted