Compaq Computer has power but it's not booting up?

Question

My Compaq Presario SR1620NX turns on, but the hard drive is not engaging. I usually hear the hard drive start, but I don't hear it now.

I think that perhaps the problem is with my motherboard battery or the hard drive. I honestly don't really know though.

Here's some stuff that's going on:

• Hard drive indicator is yellow
• Power light is green
• CD drive is recognized (lights blink)
• Fan is blowing at high speed (don't think it ever runs this high)
• The CPU is very cool

Any ideas?

Answer 1

The information you've provided is helpful, but still a little incomplete for helping diagnose your problem. It would be helpful if you could answer some questions.

1. Does anything come up on your screen (such as either the motherboard's splash page, or the BIOS status information)?
2. If so, how far does it get? What happens when it gets to that point? What is the last thing it does?
3. Has there been any thunderstorms or electrical glitches (regardless of cause) prior to your computer issues?
4. Have you noticed your computer's clock changing to a time that it shouldn't be? If you can access the BIOS settings, is the time it shows correct?
5. Did you hear any kinds of popping sounds before the computer went bad?
6. Have you noticed any odd smells coming from the computer?
7. When was the last time you cleaned out the physical computer?
8. Have you moved the tower before the problems started?

From what you have provided, though, I'd venture to guess that the motherboard fried somewhere and somehow, or the power supply is about dead. There are a few things you can do to verify this:

1. Open your tower and look at the capacitors (the cylindars that stick up off the motherboard with metal tops). The tops should be flat. If any of them are rounded (these are known as "popped capacitors"), then your motherboard is bad. If the motherboard is bad, there's not much point in trying to just replace it, you're better off buying a new computer. Keep in mind, that even if there aren't any popped capacitors, the motherboard could still be bad.

2. If you have a voltmeter, you can check the voltage output of the power supply. You can do this by pulling the power cables that go to your hard drive and motherboard and check the ends against the standard values (which you can pull up on the Internet). If any are out of the accepted ranges, then at least the cable is going bad. If the bad cable is to the drives, then you might be able to use a different cable (remember to check it!). If more than one drive cables are bad, or if the motherboard cable is bad, then the power supply is bad and will need replaced.

3. Try cleaning the physical machine (you can do this with compressed air, such as canned air, or an air compressor on a pressure less than 60psi) and reseating all the power connections (especially if you moved the computer recently). It's possible it's just the connections have loosened (not hugely likely, but worth trying).

Answer 2

It's not the motherboard battery. It could be the motherboard. But I'm getting ahead of myself.

The symptoms you're describing indicate the system is probably not completing the POST (power-on self-test). There are countless reasons this could be happening. Here's the basic troubleshooting I go through in such a case, and they are an effort to narrow down where the problem resides.

Shut down the PC, disconnect all the cables and pop the case open. Stick your head in the case and smell. If you get a very acrid scent in your nose -- which can only be described as 'that burning electronics smell that sticks with you for days and you never forget' -- things are very bad. Otherwise, blow any and all dust out of the case, preferably outside.

At this point you could try connecting the PC again to see if the problems are fixed. You would be surprised how often simply cleaning the dust from a PC fixes serious issues. It's also a good time to check to be sure that all the fans are spinning when the power is on. If only the power supply fan is running, that gives you an idea of where the problem is. Assuming that doesn't help...

Taking note of where things connect, disconnect the CD drive and hard drive from the motherboard and power supply. Remove any adapter cards. Disconnect any USB headers for the case. If you have onboard video, even remove any discrete video adapters and connect your monitor to the onboard video. Otherwise if the discrete video card is the only video adapter in the system, you must leave it in place.

Remove all but one stick of RAM, but make sure the lowest numbered slot is still populated. That is, look for writing next to slot. On some systems, it's the closest to the CPU or back of the case, and on others it's the furthest from the CPU or back of the case. Look for slot 0. Leave RAM in slot 0 and remove the rest.

Examine the system board. Look for any obvious signs of burning or damage. Look at the capacitors (the cylinders) and see if any are bulging or oozing liquid.

Connect the power and monitor to your computer and turn it on. What we have done is taken your computer to the bare minimum required to boot a computer: CPU, RAM, display, motherboard, power. A computer requires these things (and only these things) to complete the power-on self test. There is no input device so after the BIOS show the computer will probably complain about no disk, having nothing to do, or display a blinking cursor in the upper left corner of the screen.

If the computer completes the POST in this case, turn off the computer and reconnect something. I'd start with the remaining RAM, if there was any. Keep going until you find the device that breaks the computer. Either that device is faulty or the device it connects to is partly faulty (for example, the disk controller on the motherboard might broken, but it only causes a problem when a disk is connected to SATA-0). Replace whatever you find is causing the problem. In our example, I would replace the disk and the cable connecting the disk first, then the motherboard if I discovered a known-good disk caused the system to fail.

On the other hand, if the symptoms persist on the computer when all you have connected are the basic components components, then the problem is in one of those components. At that point, there are some rules of thumb.

1. RAM is the most common component of the basic system to fail. A computer with four sticks of RAM has four times the likelihood of a RAM failure. Motherboards and display adapters are in the middle. CPUs almost never fail except when something else does (the motherboard, power supply, or the CPU fan).

2. When in doubt, replace the cheaper part first. Not just because it's easier on your pocket. It's also because more expensive components tend to have more rigorous QA testing.

3. Computers are built like buildings. An apparent problem on the top floor can actually be caused in the basement. The opposite is almost never true. The basement is the power supply. First floor is the motherboard. The motherboard is the true core of a computer, as that is what everything connects to and intercommunicates with. Second floor is the CPU, RAM, and video adapter. Third is the rest of the hardware like disks, adapter cards, displays, keyboards and mice. Fourth comes operating systems and networks. Fifth is application software. At the very top is the user. You'll notice the higher the floor, the more common the problems are and the less severe they tend to be in terms of system usability (all jokes about users aside). You can also see now why it is unwise to buy a low-end motherboard and power supply when you're getting high-end processors and video cards.

4. When diagnosing a faulty system, start at the bottom floor and work your way up. Often it's easy to jump to the fourth floor, but occasionally errors there are not caused there.