Stable but randomly wont post

[room_on_fire]

Hello,
Recently my pc refuses to post first time, or after a restart. My CPU is overclocked to 3.5 (438 X 8) and Ive ran orthos for 24 hours and the system is stable, so I dont understand why it randomly decides not to post.

It sometimes does not post after a restart, but almost certainly wont post first time after its been off for a long period of time. After it does not post for a while, it reverts back to default bios settings, which i change back straight away and then it works fine. This is very frustating because it used to post first time evertime and now it wont.

Would this problem be down to the ram I have? I am considering upgrading to this

http://www.overclockers.co.uk/showproduct.php?prodid=MY-156-OC&groupid=701&catid=8&subcat=813

I have tried lowering the cpu speed, but that does not seem to solve the problem. Also tried feeding the ram more volts, but it wont boot with anymore or any less than 2.1. My CPU is on 1.525v but i dont think it is a CPU problem because as i said, ive ran orthos and it is stable

Thanks in advance for any help

 

[room_on_fire]

Update

Messed around in the bios a bit,

now when i boot or restart, instead on randomly posting, then turning off, then posting again with a reset bios it is now randomly posting, then posting again without turning off, keeping my bios settings. Does anyone have any idea as to why this is happening?

Thanks for any help