Is it an original install DVD from 2005 or 2006?
It may be starforced - and the StarForce drivers of SH3 do not work with VISTA or WIN7.
You'll have to remove them:
http://www.star-force.com/support/sfdrvrem.zip
You want to read this:
http://www.subsim.com/radioroom/showthread.php?t=160118