Need Help computer won't work

Is this a new computer, or are you just installing a new hard drive? Has the computer worked in the past?

Does a power light come on on the monitor? If not, is it plugged into the mains and switched on properly? Is the signal lead from the monitor plugged into the graphics card in the back of the PC properly?

Do you see ANYTHING at all on the screen or is it really "just a black screen" as if it's switched off?

Does the PC make a beeping noise a few seconds after you switch it on? One beep or several beeps?

Erm, I'm getting a bit confused here - this seems to be a 'two for the price of one' kind of thread!! You haven't fitted the new hard drive yet have you? The problem with the blank screen has just started happening and you haven't installed any new hardware or software just before it happened?

I know that a lot of people think an internal speaker is pointless when you've got 2 big speakers outside plugged into your sound card, but it's REALLY useful to hear the diagnostic beep codes when it starts up. Most PCs give one quick beep to say that everything switched on OK and it's going to load Windows ... but your PC might be trying to beep like mad to tell us what the problem is. Any chance you can connect the internal speaker? Without it, please pick from the following list of possible causes!

Processor voltage out of range
Processor speed setting incorrect
Memory faulty or loose
Graphics card faulty or loose
CMOS battery failure
BIOS settings lost or incorrect
Power supply problem
Floppy drive not connected properly or faulty
Keyboard not connected or faulty

Originally Posted by Pip

the monitor turns on and works fine

So do you get a completely blank screen or does any information appear on the screen at any point. When you switch the PC on, after about a second, you can normally just about hear the monitor try to fire up and display a picture when the graphics card initiates and sends it a signal. Do you hear that?

To turn off the power, you need to hold the power button in for more than 4 seconds usually. This is an intentional design of ATX system cases that means you can't accidentally switch the PC off by knocking the power button.