Power Supply Turns on by Itself

I'm not sure what to tell you, other than I had a very similar problem, fixed it once, never truly figured out how, it happened again, and I never was able to fix it. I spent US$40 on that motherboard, and it is now worth ~US$100. Both times it happened, I had plugged in an IDE cable backwards, but the last time, plugging it in right helped nothing, unplugging everything did nothing, I even got ahold of a PCI POST card, which showed voltage getting to the mobo, but there was no code, I changed PSUs, I changed CPUs, I changed video cards, RAM, everything I could think of. The number display stayed as dead as the motherboard itself.

I hope this isn't the case, but this is awfully similar to what happened to me. I wouldn't wish this upon my worst enemy, especially if it's a motherboard you did research for, specifically bought because you wanted a good, non-OEM board, and finally had that piece of the puzzle complete, just to have it die.

Every time I think about that board, I still get irritated. I had a good quality, fine, stable non-OEM motherboard, and just because my stupid self wanted a Quantum Bigfoot HDD alongside my 6.4GB Quantum Fireball, I now have only my Gateway OEM board, which I'm thankful for, but that put me back to square one regarding that.

Take a closer look at that socket, however; I had an ASUS P5K-SE come in the mail once, showing semi-similar symptoms, and when I looked close at the socket, I saw that two or three pins were slightly out of alignment. I took a very small screwdriver, and sweated bullets as I tried my best to bend them back. I put the CPU in, and bam, there was a POST screen, and the system was alive. At first glance, the socket looked okay, but the pins were just off enough to where they couldn't make contact with the CPU.

I'm having almost the same issue with a LGA775 bought on aliexpress, sometimes it turns on just after the psu is powered and then shut off, other times I have to use the pw button but the behaviour is the same.
I suggest to make it start without the cpu, in my case if without the cpu the system starts and stay on, otherwise it keeps doing on-off, or it could be a bios corruption, you will need to flash the bios using a programmer.

probably bad power supplies and I had a similar problem before using a bad powersupply and it broke my motherboard.

Is it a Asrock 4CoreDual-SATA2 or 4CoreDual-VSTA ? The 4CoreDual-VSTA requires BIOS v1.80 to support Q6700. The 4CoreDual-SATA2 supports it on all BIOS.