AMD Phenom II X2 550 Regular Edition Overclocking and Unlocking

So, the title says it all! I read all the information about overclocking and unlocking the 4 cores and tried, but I need a lot of help since I am a complete novice when it comes to that matter!

Processor: Phenom II X2 550 (NOT Black Edition)
Mother Board: GA-785GMT-USB3 >> It has ACC and the specified South Bridge
Ram: 6 GB DDR3
VGA: MSI GTS 450 1 GB >> Not Overclocked

So, this is my specifications! Now when I got to unlock the cores, I change ACC to Auto and change the other setting from Normal to Hybrid, save! The PC immediately shutdowns and after a few seconds it starts again, but the ACC is back to Disabled and nothing happens. No cores are unlocked! Ideas? I know the 2 cores may be defected, but I need to have my chance trying. Do I need a more powerful Power Supply? I don't know mine, but it's not high, think a 350W Gamma Power Supply should do it? This is just my budget right now! So I hope you can help me out here!

When I think about Overclocking and of course can't do it without upgrading my Power Supply, yet I found that my max. is 15.5X which is exactly 3.1 GHz the normal for my processor, so I am stuck and don't know what to do! Also I need a detailed guide about Overclocking and what I need to do to increase the voltage the Processor needs. Another matter is the temperature, it's 58C without overclocking and I think this is not good when I overclock the processor, so I need to change the cooler. If so, how and what cooler do I need (not an expensive one since my budget is low right now).

I think that's all for now! I really wish you could help me and that I succeed in those matters! Thanks in advance