My computer also has this problem, it usually beeps once then the computer will start up normally but now it does not even beep and it says "no signal" on the screen so I got no idea how to fix it and I am not an expert in computer so there are many components I do not know... what shld I do?

First, its not a good idea to piggyback your question on another thread. To avoid confusion I've moved your post to its own thread.

The beeps indicate there is a problem with the motherboard. You need to take it to a shop or replace it.

{Mod Note: Threads merged}

My computer used to beep once before starting up but recently my computer stopped giving the beep sound and displays the words "no signal" on the screen, can someone please help me with this problem

Check your RAM (Memory)

Its broke... take it in for repare or buy a new one. If its more than a few years old... buying a new one is a better option.

The computer will give the beep sound when it is starting up as a test to make sure the computer has everything hooked up and running that it may need. This also depends on the age of the computer. Older computers will not start up with a USB keyboard for example, they require a P/S keyboard. So I recommend making sure you have a mouse, keyboard, and monitor plug into the computer and that all the connections are good and tight. Based off what you typed in your question I would say the monitor works because it is displaying "no signal", and maybe the VGA or DVI cable isn't plugged in tightly and has come loose on the connection on the monitor or desktop end.

Hope this helps, good luck!

I understand that you're not an expert with computers, but do you know if there is any 3rd party hardware installed in your PC. i.e. an external video card or something similar?

No, there isn't

Once I had the same problem.
First of all leave you computer to cool down for a couple of days.
Don't get impatient. If it's possible then open up the CPU and just clean the dust without removing any component of it.
(Sometimes wires may get lose or there may be a breakage in your CPU component, be sure for it)
If still it is not working then you can say that your motherboard is having a problem.

If you don't hear anything at all when you press the power button, including no fan noise, it is most likely a dead power supply. Whether the power supply is replaceable depends on what kind of computer you have. Some name brand computers have power supplies that can only be replaced by the manufacturer. In that case, it might be cheaper to replace the computer. If it has a generic power supply, a computer repair place can replace it easily.