Error – “My Computer won’t come on, power on, or boot up.” – Updated
N8 March 13th, 2009View/Print PDF Version
“My Computer won’t come on, power on, or boot up.” – First off there are a number of reasons that could cause your computer not to power on, or “boot up” and there is no way I can cover them all here…but will cover some of the most likely candidates.
We will start with the basics. I hate to ask, but being in the computer industry for as long as I have this question has unfortunately became necessary – Is your computer plugged in? Yes, I know, a seemingly dumb question but I have found that many times the cord gets “accidentally” unplugged by cleaning or a foot under the desk. Also related to this is if it is plugged in is the power strip on? Has the surge suppressor been tripped?
You do have a surge suppressor don’t you? Don’t risk your computer in order to save $50 bucks or so. Surge suppressors are the first wave of defense against power problems and they are a necessity if you want to keep your computer running. I would actually recommend getting one with a battery backup in them which also helps to protect you from “brown outs” which are dips in the voltage without actually being a “black out”.
The power supply would be the next obvious culprit. Your power supply is the box that your pc’s power cord plugs into. Make sure that the switch on the back is in the on position (usually minus down).
They make power supply testers that test the power supply on a basic level. For example I have had power supplys pass the basic “on/off” test but not be able to actually power a computer, so at this point you have a couple options. You could take your computer to a pc repair shop and let a technician diagnose and/or fix the problem…or you could replace the power supply.
The reason I suggest replacing the power supply even though we aren’t entirely sure that it will fix the problem yet is for a couple things. First power supplys are the problem on at least 8 out of 10 computers that I fix that won’t boot up. Power supplies, at least the basic, budget ones are relatively cheap. Your local computer repair shop probably has them in the $50 range or less. If you are running a high powered machine with multiple hard drives, cd rom drives, video card with additional power needs, etc. then you may want to opt for a higher quality power supply. Some brands that are good quality are Thermaltake, Antec, or Cooler Master to name a few.
The power supply is usually held in by 4 screws located on the outside of the case. After this it is usually just a matter of unplugging it.
If you replace the power supply or know that it works in another pc then the problem is probably the motherboard…although it could also be a bad power button, the latter is rare though most folks hope it is as simple as that.
My Computer Powers on, but will not POST (Power On Self Test)
If none of the above symptoms fit and your computer and it powers on but won’t go any further then it is not “Posting” which is the lingo for POST Power On Self Test. This is the tests that the computer does, or should do, when it first comes on. If you power it on and no writing appears the problem could be a malfunctioning component. Some pieces of hardware that could cause this problem is the cpu, motherboard, ram, video card, or even an installed component like a modem or network card. The latter is rare but I have had bad modems and nics not allow a computer to POST.
Look now and make sure that your cpu heatsink fan is able to move freely and the fins of the heatsink are clear from dust. If your processor is overheating it will automatically shut off your computer. If that is clear you may want to wiggle the heatsink to make sure that something hasn’t broken on the clamps to cause it to not be seated properly. This is common with socket 478 motherboards, but others do it too.
My recommendation past this is to unplug components one at a time to try to narrow down the culprit. If your computer uses DDR2 ram I have found that the ram has quite often caused a computer not to post if it is bad. Remove the ram one at a time and try different slots, be sure to get it seated properly and don’t force it in the wrong way. If you take both bars of ram out and don’t hear any beeps it isn’t a good sign.
Typically bad ram is signaled by 3 long beeps. If you remove the ram and hear 3 long beeps then that very well may be your problem. Ram is cheap so replacing what you have shouldn’t be that expensive unless you have high quality aftermarket ram..if you do you will know it.
If you remove the ram and leave only the motherboard and cpu plugged in and don’t get a beep or post of any kind then you have narrowed down your problems. Usually if you get this far the problem is the cpu. But it could also be the motherboard. I would price shop and replace the cheaper component first. Depending on what you have this will usually be the cpu.
If you get a CMOS error on boot up this is usually an indication of a bad battery. The battery is usually located on the motherboard and is a “coin” style that resembles a shiny quarter. These can usually be found most anywhere. Once replaced enter your BIOS (Basic Input Output System) usually accessed by pressing F1, F2, or Delete on boot up. Once in set your date and time and save the changes. This will usually quiten the CMOS checksum errors. If it doesn’t your BIOS may have became corrupted in which case you will probably have to replace the motherboard.
My computer posts, or boots up, but will not enter Windows (or other Operating System)
If your computer passes the points above and won’t load Windows then that is a whole new can of worms. There are so many things that could cause Windows not to load that there is no way I could cover them all.
So I will try to cover the most likely ones.
First press F8 just before it begins to load windows and select “Last Known Good Configuration”. If it was a setting change this will usually fix your problem.
If that doesn’t work you maybe getting a “Stop Error” in which case follow the instructions in the “My Computer Restarts Automatically or for No Reason” article.
If you do that and still can’t get Windows Xp or Vista to load you can try a built in ntfs function called “Chkdsk” Chkdsk has gotten many computers to boot that nothing else would. Chkdsk repairs errors in the NTFS structure and on the hard drive. The easiest way to run this utility is to boot to your Recovery Console, this is usually accomplished by booting to your Windows Vista or XP installation disc and selecting the Recovery Console. Once in type in “Chkdsk /?” to see what your options are. Depending on your version of Chkdsk the “/p or /f” would be the option you want. This option fixes errors on the hard disk but doesn’t scan the surface of the disk.
If you can boot into Safe Mode then your problem is more than likely driver or program related. Safe Mode basically functions by not loading all Windows drivers.
If you can boot into Safe Mode attempt a System Restore which is usually found under Accessories -> System Tools in the Program Files menu.
Beyond this your problems could be spyware/malware related, a failing hard drive, bad ram that corrupted system files, or even a bad hard drive cable. Unfortunately there is no way I could cover everything here but hopefully something in the article helped.
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It may even be necessary to replace a fan that may have quit working. Don’t forget to check the Power Supply ( The box your Power Cord Plugs into) and make sure that it’s fan is working and that it is not clogged up with dust. Some power supplys have two fans, so be sure to check them both. If the area where your computer is is hot this may cause issues too, and you may need to drop the temp a few degrees to get more stability. This is a likely culprit if the problem happens more the longer your computer is on. This is because the power supply gets hot and if it is not adequately cooled it will not function properly. The same thing goes for your cpu. IF the blades on the cooler of your cpu are clogged with dust or the cpu fan isn’t turning this will definitely cause problems.
