There are times when your PC will not boot up reliably. Then again these days it’s quite common to come across an XP PC that suddenly will not boot up at all.
A visit to a technician is probably called for. Hoewever, if you must try and repair the PC on your own…
Check if the screen remains blank when you power up. Is the Windows load or at least the motherboard/BIOS splash screen displayed?
Check if there is an error message? Is there perhaps a white cursor arrow visible? Does the system beep? Is the fan continuously spinning albeit unusually fast and loud?
Try using a different monitor and video cables. If you’re technically adept, you might want to try replacing the power supply. If nothing works thus far, its probably a underlying hardware problem. If the computer is more than a few years old, then expect hardware failure.
The fact that the PC is not beeping and the screen remains blank, even though you have it properly connected, implies to me that the CPU (the computer) literally is not running.
Even though the power might be on, the fans might be blowing, and you might even see some lights somewhere, that doesn’t mean that the computer itself is actually doing anything.
That, then, has me focusing on the computer’s motherboard itself.
What I would do, to begin with, is remove any add-on cards that aren’t absolutely necessary. For example, if you have a network card, a sound card, whatever. Any additional add-on cards. Also, go ahead and disconnect all of the USB things (if there’s any USB on there)… that you can get by without running.
Disconnect all that and see if that does anything.
Then, you might start looking at components on the motherboard.
It’s very possible that simple things like the RAM not being completely seated in its sockets could cause a problem like this.
The processor, itself, not being completely inserted into its socket could cause a problem like this. Unfortunately, it could be caused by any number of things on the motherboard. That makes it extremely difficult to diagnose. Unfortunately if you’re not a technician, and you don’t have the right kind of tools, it becomes almost impossible to diagnose.
So begin by removing any cards, any add-on cards that you can. See if that makes a difference. Reseat all the RAM and potentially the CPU, if that’s possible, and then see if that makes any difference.
If it doesn’t help, you might consider removing all of the RAM except for one (if there’s more than one.)
Sometimes faulty RAM can cause this kind of a problem.
Ultimately, your options, without reaching for a technician are very, very limited. So give those kinds of things a try. You might get lucky.
In the long run, you could also, of course, end up replacing the motherboard; but that begins to push the envelope of what’s cost effective. If it looks as if spending money is unavoidable, either on something like a motherboard, or as you say a technician, it might just be time to look at a new machine.