Recently my Asus P5B board started developing something of an itch when booting cold (after 10+ hours off).
At first, around december, it would occasionally not recognize the primary hard disk but after a simple restart it was there again. Later this happened every single time I turned the PC on. About a month ago it wouldn't boot at all. Everything started turning and the lights went on but no beep and no output on the monitor. Back then I took everything non essential out, it booted and I gradually put t back together again. It just worked so I have no idea what could have been the problem.
Today this happened again and I couldn't bring it back to live yet...
So what I would like to ask is if anyone has an idea what could be wrong here.
The board is about 5 years old, so is the HDD and most of the rest of the PC.
My best guess as to why it does not see the HDD at first start but does when restarting ater 15 sec is that some contact on the board failed and comes back together after a little warm up due to thermaml expansion.
In short: Is my MoBo failing due to old age or is something else wrong?
I wanted to keep the system until summer and then go i5-2500 but if it keeps playing tricks on me I might have to ditch it sooner...
It sounds a lot like the problem they found with the initial release of the Sandy Bridge motherboards, where the SATA controller would deteriorate over time until it failed.
You could have a similar problem, where heat eventually caused something to fail.
One thing that occurs to me is that dust buildup in the PC could cause things to not vent heat as well, causing the problems you see. It could even cause fans to stop working right. Did you try cleaning it?
Other than that, it sounds like something on the motherboard or HD has failed, in which case you need a new one.
Try all the SATA connectors too, just to see if that is it.