Usually what we see in this scenario is that the overclocking of the FSB ("base clock") causes the RAM frequency to get too high and the RAM becomes the cause of the instability. When you overclock with the FSB ("Front Side Bus") all the other dependent frequencies are elevated as well. They are tied to the FSB. This includes the HT frequency, the CPU/NB (memory controller) frequency and the RAM frequency itself. So to compensate for that you need to lower the multipliers for he HT and the CPU/NB and start the RAM at a lower frequency divider. If anyone of these dependent frequencies gets too high they can become the source of instability.
If you would download and install CPU-z and then attach pics of these three tabs: "CPU," "Memory" and "SPD" it would be a great help to us in helping you. Please attach pics directly to your post rather than linking them. To do this, use the built in form tool. Third icon from the right end of the toolbar of any new post window.
Having said all that, there are other potential causes of instability.
1. The motherboard having exceeded it's potential for raising the FSB. Cheap motherboards like you are using often crap out when the FSB is raised beyond about 250 mhz. They have a "metronome" as it were that can only be pushed so far.
2. The motherboard's VRM (Voltage Regulation Module) exceeding its thermal limits. Cheap motherboards cannot handle much overclocking because these components get too hot.
3. The CPU core voltage being too low. At 1.375 yours looks to be too low to achieve much of a stable overclock.
4. CPU/NB needing more volts.
5. CPU cores exceeding their thermal limits (i.e., getting too hot). What kind of CPU cooler are you using? Stock OEM? Aftermarket? How about giving us some more details like this. Have you been monitoring core/package temps? HWMonitor is a good freeware program for doing this. And you will also need to do some systematic stress testing to establish true stability of the overclocked state. We generally use Prime95 for this. It's freeware. Passing a two hour "blend" stress test should confirm stability.
Get those pics to us.
Your motherboard is kind of low end and you can't expect to get a high overclock with it.