Have you ever had this problem: you turn on your computer, but the monitor shows nothing – the screen is blank? I have encountered this problem many times and I found that the cause wasn’t always the same.

There are a few things you can do to find out what is causing this, but I would suspect a faulty power supply first. It helps if you have some spare parts for testing, such as second power supply, another video card and perhaps a spare memory module (RAM). That should help you find the cause fairly quickly.

First of all, make sure the monitor works. Simply connect it to another computer and test it. Also, check if the power cord is connected properly to the monitor and the monitor cable to the PC.

Before you start testing the parts mentioned above, unplug the power cord. When you open the case, touch any piece of metal to discharge static electricity. You have to do this before you start touching any components in the PC. Then check all connections and see if everything sits tight: video card, motherboard, RAM…

If everything sits correctly, you must test a spare video card in the system. Check your PC manual to find out if you need a PCI, AGP or PCI-Express video card.

If this works too, then test a new power supply. Faulty power supplies often cause this problem: even though they might work, they don’t provide (enough) power to the motherboard and other components to run.

On the other hand, if a new power supply doesn’t work either, then test a new memory module in your computer. Faulty RAM has caused the same problem in at least one PC I had to repair. Again, consult your PC manual to find out which RAM you need and try to find a spare one for testing.

Finally, only the motherboard and the processor (CPU) are left, but they rarely fail (in my experience). Motherboards can fail but it is difficult to see this unless you see blown capacitors on the board. CPU probably wouldn’t cause the problem.

I hope you will find that either a power supply or video card change will solve your problem.