Diagnosing Computer Start Up Problems
If you are having problems with your computer not starting up at all, please refer to the article My Computer Will Not Turn On.
The key to fixing computer startup problems lies in knowing HOW the computer starts up and what it does. When the computer first starts up, the BIOS loads from ROM (which are memory chips with software on them). The BIOS tests the computer, controls some hardware and software settings, and directs the computer to an operating system or other program to run after it is done loading its settings and performing its tasks. If there is an interruption with one of the BIOS' first tests (its POST or Power-On Self Test; which tests the existence of the computer's keyboard, mouse, RAM, processors, hard drives, disc drives, and others), this indicates a hardware problem that requires attention (refer to my article on solving software and hardware problems on this website). If this test is passed, the BIOS looks for an operating system on any bootable CD/DVD, hard drive, USB disc drive, etc. If it cannot find anything, it displays an error message such as "Non-system disk". If the computer passes this test, Windows or another operating system begins to load. If this messes up, Windows enters Safe Mode or your computer turns off because you have a software problem that is most likely a corrupted Windows registry, missing Windows file, or hardware conflict (refer to my Hardware and Software articles for more help on these topics). A computer may also not start up correctly if there is a problem with the computer's slave/master configuration (article coming soon). Before checking your computer for start up problems, please check for basic things such as the electricity outlet that you use for your computer is working, your computer's power light turns on, and the computer monitor's brightness is set to a reasonable level. Also, if your computer's BIOS moves too fast for you to see what's going on when your computer turns on, press the pause or break key on your computer to try and slow down the startup process.
What do I do if I have a "Non-system disk" or similar error?
The non-system disk or similar errors can be caused by a variety of things. Some of the most common reasons for these errors include:
-there is no operating system on your computer
-your computer has been infected by a really bad virus
-a blank bootable CD/DVD is in your computer's optical drive
-your computer has recently overheated and the hard drive or computer is protecting itself from overheating again
-the boot manager isn't looking at the hard drive when the BIOS is loading
-your hard drive is having boot sector or similar issues
-your computer is having internal electrical problems with the motherboard
-your computer's hard drive cables have become unplugged
Specifically, the "Non-system disk" error usually comes from:
-a blank bootable CD/DVD is in your computer's optical drive,
-your computer has recently overheated and the hard drive is protecting itself from overheating again
-the boot manager isn't looking at the hard drive when the BIOS is loading
-your hard drive is having boot sector or similar issues
-your computer is having internal electrical problems with the motherboard
-your computer's hard drive cables have become unplugged
The "no operating system error" usually comes from:
-there is no operating system on your computer
-your computer has been infected by a really bad virus
-your hard drive is having boot sector or similar issues
-the boot manager isn't looking at the hard drive when the BIOS is loading
What problem is my computer most likely to have?
First think about what you have recently done on your computer. For instance, if you recently moved your computer, the most likely problem is loose computer hard drive cables or an internal electrical problem and I would try tightening the computer's hard drive cables first. Considering all things equal, the best way to check your computer for problems, in descending order, are for: overheating, loose hard drive cables, a boot manager problem, a blank bootable CD/DVD in your computer's optical drive, a computer virus, the no operating system on your computer problem, the boot sector or similar hard drive problem, and finally the internal electrical problem with your motherboard's hard drive controller. Please keep in mind that when trying to fix these kinds of computer problems, it is unlikely that you have lost access to all of your computer's data. To get your data back, refer to my article on Booting up Puppy Linux that is coming soon (in Puppy Linux, you can probably find your files and put them all on an external hard drive).
To fix the no operating system on your computer problem, install or repair the operating system as quickly as you can! Typically you would need a bootable CD or DVD with Windows or another operating system and/or emergency recovery discs that you would put in the optical drive just as the computer starts so that you can install or repair the operating system on your computer.
To fix the computer virus problem, use a bootable CD/DVD with a program like this (Bootable Antivirus Rescue CD) on it so that you can try to disinfect your computer and restore access to your Windows installation.
To fix the blank bootable CD/DVD in your computer's optical drive, remove any discs from your computer's optical drive and restart the computer.
To fix the overheating problem, open the computer case and clean the computer with an air compressor and a cloth. Also wait a while for your computer to cool down and if it's over 32 degrees Celsius outside, don't run your computer at all!
To fix the boot manager problem, load the Setup Utility for the BIOS by pressing F2, F8, DEL, or a similar key when your computer loads. Once in the setup utility or boot menu, look for the boot manager, boot priority settings, etc, and see if you can make the first boot device your hard drive. When you are done, save the changes you have made and exit the setup utility (which will probably restart the computer).
To fix boot sector or similar problems with your hard drive, refer to my article on fixing bad hard drives. However, please note that these kind of hard drive problems are usually difficult to fix and you may need to contact data recovery services in your area.
To fix internal electrical problems with the motherboard, refer to my article on installing and replacing motherboards coming soon. Most likely the motherboard's hard drive controller is broken and that is why you need a new motherboard. You can also contact a computer repair service or the computer company to fix this problem if you feel uncomfortable about fixing this kind of issue.
To fix unplugged computer hard drive cables, simply open your computer's case and make sure the power and data cables that are attached to your hard drive are tightly plugged into the hard drive and the data cable is tightly plugged into the motherboard on the other end, and the power cable is tightly attached to the power supply on the other end.
If you don't know what kind of problem you have, try to do the simple tasks first (like making sure the hard drive cables are tightly plugged in; ensure that you wear a static strap that is grounded when working on computer components and pressing F8, F2 or similar key when the computer first turns on, so that you can load the boot manager and ensure that the hard drive is the first boot device; unless you're booting off a CD/DVD). Also, remember that pressing F8 before Windows loads is a good way to try and run Windows normally through Last Known Good Configuration or Safe Mode.