Hello and welcome to the forum.
Please read the first post in this sticky thread here How to ask for help with a BSOD problem
Do your best to accumulate the data required.
Run the SF Diagnostic tool (download and right click the executable and choose run as administrator)
Download and run CPUz. Use the Windows snipping tool to gather images from all tabs including all slots populated with memory under the SPD tab.
Likewise RAMMon. Export the html report, put everything into a desktop folder that you've created for this purpose, zip it up and attach it to your next post (right click it and choose send to, compressed (zipped) folder.
I did notice that you are running BIOS Version 0503 01/05/2010 which is 5 or 6 version numbers behind the current version 0801 02/28/2011 which looks like a good one since it would seem to address (Improve memory stability, Improve system stability.) http://www.asus.com/Motherboards/AMD_AM3/M4A78LTM_LE/#download
The problem came back again after about 10-15 mins of game play. I tried all the suggestion on H2S04 guide minus the reinstallation. I don't think anything is overclock cause I have no idea on how to do it in the first place. The crash only occurs when i'm gaming. Here are the lastest minidump file.
Another 124, still hardware.
Download Memtest86+ from this location here. Burn the ISO to a CD and boot the computer from the CD from a cold boot after leaving it off for 20 minutes or so.
Ideally let it run for at least 7 passes / 6-8 hours. If errors appear before that you can stop that particular test. Any time Memtest86+ reports errors, it can be either bad RAM or a bad Mobo slot. Perform the test RAM sticks individually as well as all possible combinations. When you find a good one then test it in all slots. Post back with the results.
See this Guide to using Memtest 86+
After days of testing. I think I finally found the problem. Before my last crash I noticed my cpu temperature was at 90-98% before it crash. What I did was I open the side of my computer and used a house fan. Been playing game like that for 4 days now and haven't had a crash yet. So it seems I need a new fan. Should I change the heatsink also?