If possible.. Try to format your pc, Re-Install windows and install BD then, I had those errors loads before with games its mostly random software you have installed that ruins it all, I formatted my pc after I couldnt find out what was wrong, re-installed those games and worked fine, but this is just your last possibility don't format unless theres no other option(s) left. <img src="/ubbthreads/images/graemlins/tongue.gif" alt="" />
//Inel.
There are simplier solutions than a full system reinstall.
You can try to defragment your hard drive. If it won't help, it won't hurt anyway.
Check for spyware with Lavasoft's Ad-Aware.
Disable Norton Autoprotect if you have it. Remove unnecessary programs. Check for suspicious programs running in the background. It could well be a worm, a RAT or some other poisonous vermin.
Finally, check for hardware conflicts.