I am really getting mad. Should i blame intel or corsair for this .
What i am not getting is that the original dp67bg and tx750v2 worked like charm but what the hell has happened with replaced dp67bg.
The problem is due to a combination of both (and possibly even the BIOS version and AA revision of the board). You could use your 600 Watt PSU to get it up and running then flash the BIOS to the same version you had with your old DP67BG (or possibly the newest version may work fine). You could then swap back to the 750 Watt PSU and test again. Sometimes small changes are made with board improvements (BIOS revisions and AA revisions) regarding voltage tolerance acceptance and perhaps the new board expects a slightly finer tolerance (as is) than your old one?
Sorry to bump this but I'm having exactly the same problem. My previous Antec 500W power supply died, so I purchased a Corsair TX850M from one of my suppliers. After fitting, the PC will switch on but the BIOS indicator on the motherboard just displays 00. There are no POST beeps, but all the devices are powered up (although the same thing happens if I disconnect everything except the essentials).
Thinking the PSU was faulty, I had it replaced but encountered the same problem. I returned that and last night tried a Fractal Design Newton R2 800W power supply and that does the same thing.
If I try a Corsair CX430 (430W) or a Fractal Design Integra 400W power supply then the system will boot perfectly but because of my graphics card, it is running a little too close to max load for my tastes, so would prefer to have the higher spec PSU if possible.
It wasn't until the Fractal Design PSU also didn't work that I started to think it could be the motherboard and a quick search here this morning highlighted this thread. The problem I have is that the motherboard itself is not actually faulty, but clearly doesn't like these power supplies.
I updated the BIOS not that long ago, but cannot guarantee it has the latest February release. I will try that tonight to see if it makes a difference.
As it's clear that your choice of PSU has something to do with this, what does the PSU maker or seller have to say about the matter? I suggest you point them to this thread if they didn't already know about it. It's also worth formally raising a Tech Support ticket with Intel as if it's being looked at by both sides, then there's more chance of a resolution being achieved.