Computer fails to boot, no beeps
I have an odd problem with my computer @ the moment. When I turn my computer on, sometimes it can fail to boot. The computer turns on, their is no beep unlike usual and there is little actvity (The power LED turns on, the hard drive light stays on, fans spin, but I don't think the hard drive goes). The screen does not come on. The power light will stay on briefly, but will start flasing again indicating it goes back on to stand by. Nothing else happens. The only way to make it work is to turn it off and on again. Most of the time, it will then work fine.
I have done three things to my computer that could have triggered it. I have recently upgraded the PSU, but I had no problems with that and the problems started a while afterwards. I have swapped around the RAM a couple of times (I bought 2 new sticks, but they did not work, and they became damaged, proberly fried. I don't know if they did any damage to other components. Either way, I am now back to my old sticks of RAM). Lastly my CPU fan has became very noisy over the last couple of months, to the point which I took it out, cleaned it up (just the fan, not the heat sink) and put it back in. It was after that I noticted the problems . The fan still becomes loud now and again.
Its only occasional but often enough to warrent suspicion. It does'nt happen just after extensive use, it can happen on the first boot of the day, so I doubt its overheating. Does any one have any idea what it could be?
I have read a couple of places that it could The PSU, RAM, MB or over heating. But this is'nt a constant problem, its only every so many boots. When it does'nt happen my computer works fine.
Any help would be great full, I have no idea what to do.