Getting snowy picture at random times

[preceptor]

Okay heres what i am using:
40" samsung 1080p
hdmi to dvi cable

Pc:
msi mother board
2.8 ghz intel cpu
8600gt 512mb nvidia card
onboard audio to speakers not controlled by tv

problem: blu ray player is maximized on tv (second monitor), i start a movie and between 2-10mins into the movie it goes snowy and blanks out the whole screen. if i adjust the display settings at all the movie re appears and its fine for another couple of minutes before it does it again.

i had this setup on my gaming machine that was running 2 8800gtx in non sli and it worked fine (tv was the third monitor).

Do i need to remove my pc monitor and use just the tv as the only monitor for the pc for this to work? or is there another problem.