I just went back and read your old thread
You used to have 4 sticks of 512mb ram, and discovered that 2 were faulty. So, you have been running with 2x512mb ram for a while without any problems, now your two replacement 512mb ram stick arived and when you try and run all four sticks your game is still freezing up on you. Am I up to date?
Just to confirm:
1. you say this ONLY happens in WoW? When you play other games, or other software you have NO crashes what-so-ever?
2. the previous two sticks passed ramtest without errors
3. you have the latest graphics card drivers
4. you have the latest motherboard chipset drivers
5. you have the game's latest patch (if there are any)
Also, can you please post your PSUs information? It is not in your profile. If all the above is true, this is the next bit of hardware I would look at. It is a possibility that when you pop in the additional ram it is putting your PSU over the edge. Gaming taxes all your components and tends to be when a PSU starts complaining. If you are using the PSU that came with your case (Aspire) then I would say this is an EXTREMELY high probability that this is your problem. Aspire PSUs are ..... to put it straight, complete trash.
Another possibility is that you need a bios update. Check your bios and see how many have been released since you last updated. Some motherboards have a hard time running with 4 sticks of ram, and bios updates may help.
I would also (just for your own information) take a look in your bios and see what frequency your ram is running at. You have a socket 939 based cpu, and many of them are not good at running with 4 sticks of ram. There is a good chance that your system is automatically underclocking your ram to 333Mhz once you install the additional 2 sticks. Have a look and see to confirm.