[HELP] The computer does not post

I have problem with my computer after half year. When I turn it on, from outlook everything work well like fans, light.... But mostly it does not post anything on the monitor. It always says "No signal".

However sometimes when I turn on it works normally. I notice it only works incase the HDD light is on during booting process.

I tried to test my drive in anther computer and it is fine.

So what's wrong in my hardware components?

Of course I am very sure I checked all cables plugged in securely.

Possibly your power supply starting to pack up. What is the specification on it?

What you are saying is that your computer can not always pass POST.
Post (power on self test) tests motherboard, and short ccts, cpu, ram present, then gfx before you get a splash screen on the monitor
First question is, does your mobo bios support the cpu?
If it does, check again to make sure you heatsink is well secured, and that your gfx card and ram are fully inserted.
If all that is good, you probably have a short circuit. That can be a lot harder to find.
Start by looking for foreign objects and loose screws. While you are at it, give everything a good visual inspection. Sometimes you can see something is wrong, even if you dont know what you are looking at.
A place to give special attention is those cylinders around you chip. They are capacitors. If the top is not flat, even a little bulge, or if they are leaking at all, that's your problem.
If you still haven't found the problem, it's time to start removing things.
Add on cards, other than the gfx is a good place to start.
Leave gfx card, one stick of ram, cpu and heat sink, and keyboard till the end.
Good luck.
The best place to start is by checking that the gfx card and ram are well seated.

Try disconnecting as much as poss and see if starts OK. Most likely is intermittant motherboard problem or failing PSU. PSU can have problem starting, but be fine after initial power up. If you get beep for POST OK, but no signal, is monitor, cable problem ( or video card)

Mike.