GA-73PVM-S2H not posting Bios

[marty584]

GA-73PVM-S2H
Intel Q6600
Point of View Nvidia 9600GT
Western Digital 500GB HDD
Antec 550w PSU
Corsair 4gb Ram in 2x2GB DDR2-800 (XMS2-6400C5)

Recently changed DVD burner from Pioneer dvr212 to a liteon and now bios will not post
Same happened last month when hooked up second monitor to graphics card but did come back on after disconnecting all components and reconnecting however this time will not come back.

So far have tried -
on board graphics with 9600GT removed
on board graphics with 9600GT still connected
Disconnected all components and reconnected
Disconnected all and reconnected one item at a time
Cleared CMOS
Removed CMOS battery
Removed RAM and tried in different combinations
Tried old DVD burner again

PSU seems ok as all fans come on and all lights up etc

Still not able to see any bios after all of the above

Had same issue before I got the GA-73PVM-S2H so Im thinking something may be up case wise as case is quite old, the internal speaker is gone so I dont get the beeps.

Any ideas?

[Aussie Allan]

  Can you describe the PSU....age , brand, model. Wattage....?

  Aussie Allan

[Dark Mantis]

Antec 550w PSU

[marty584]

I am currently at work so will have to check when I get home

From what I remember it is a 550 watt Antec PSU about 3 years old.
It has 2 sata power outlets approx 4 molex ones 24 pin connection for motherboard and the 4pin 12v

The machine has been doing the no post thing for a while whenever I change any hardware (recently changed CPU fan and also added second monitor to video card same happened) it normally does come back with a bit of messing about however this time I haven't been so lucky.

The power does come on and the fans and case lights come on however the monitors do not display anything, even using the onboard graphics nothing comes through.

[marty584]

Checked the PSU and it is 550w however its not Antec

Its a delux switching power supply model atx-550w p4

Tried another psu q-tek big fan 500w and that did not help however the psu didnt have the full 24 pins Just though I would use it to test