Salar, I don't agree with you.
Try using BETTER than the 'Recommened System Requirements"....such a game does require, instead!
Using the bare 'Minimum'.....of "System Requirements".......will only serve more 'head-aches' than is necessary!
Why?
Because you (any other user, too).......are operating any game, on it's 'Minimum System Requirements'...to start with.
And, as such, you definitely are bound.......to run into constant DirectX problems.
" CALL OF DUTY WORLD AT WAR (5) ".......is pretty hard on RAM and GRAPHICS/Video (RAM) usage.
One or both (of your computer)......could actually be the 'source'...of your DirectX problem.
Not the drivers.
The fact that you are 'tinkering'....with the 'Sample Rate' (and, the like)......well, you're just compounding the problem.....you started out with.
Most Games/Programs......are used at a "Default Setting", and are best that way.
Why?
Because they (both, generally) are already OPTIMIZED......to WORK, at a safe level of usage.
That is,.......for 'normal use', NO Games.
You want to play Games, here's my advice,
"MAX your computer out, to the MAX!......in RAM/Graphics and Hardrive Capacity! Before you start playing Games..on yours."
Mine is, and I can throw anything at it, with it faltering.
If I was to change to a 64-bit OS, even better since the graphics-card I use is capable of going to 1 Gb (of Video-RAM). It's currently running at 512 Mbs, Boosted up from 256 Mbs, courtesy of the 256 Mbs...of 'on-board Graphics').
That's what I mean, by 'maxxing your computer out'.....to wit, I also have 4 Gbs of RAM, and 2 X 250 Gb hard-drives. I could use the 'on-board Sound', BUT, I don't, instead I rely on an add-in Creative Audigy Sound-card....for my Sound.
Like I've already stated, mine handles...everything I throw it's way.
(All done, on a Pension, I might add, too.)
If the computer.....is a 'family' one (and you use it to play your Games on it), SORRY, you're stuck...with what you've got, because your parents (maybe!)WON'T upgrade it, just because you want to play your Games on it, when it's perfectly OK...for everyone else.
If the Game itself...is the real cause, maybe, try Uninstalling it (this DOES include any/all Games 'Saved')......
These 'saved' games....are saved, under the usage of the OLD drivers, and, there may be a 'conflict'........between the OLD and NEW drivers. (Though there shouldn't be!)
Is there a 'patch/update' installed.....for the Game?
If "NO"...then, THAT too can be a source....for your DirectX problem!
When in doubt.....READ the 'Help' file, or the "Readme.txt File", to verify the source of your problem.
This APPLIES....to ALL Games/Programs.
(As there are many Graphics-card/Sound-cards......that just WON'T work!....with certain Games/Programs! And, the BEST place to check....is in that 'Readme.txt File'.....to find out whether what computer-components yours has....is on that List, or NOT!)
Last of all, the problem can actually be.....YOU.
Stop tinkering!