your dxdiag is incomplete.
ive not finished downloading myself so not sure whats what but first things to start with are updating all your system drivers including graphics and sound
some other things which wont hurt to check
runing a memory test using memtest
check your graphics and system temperatures, if your using catalyst control centre the graphics card fan is locked at 50% by default. you may need to try unlocking overdrive and manualy changing your fan speeds
if your using vista makesure you have sp2 installed
try downloading C Cleaner "it's free from CNet or many other trustworthy download sites. Use the registry tool in CCleaner to "fix all registry issues" . That helped my problems getting bumped from STO. I