My Computer won’t start. Why?
TROUBLESHOOTING POST PROBLEMS
POST = Power On Self Test
NOTE: When working on a computer, always maintain proper ESD (Electro Static Discharge) prevention procedures.
There are many things which can prevent a POST. An IDE (or EIDE) device (hard disk, CDROM, etc) gone bad, any plug in card either gone bad or loose/dirty, RAM bad/loose/dirty, power supply failing (delivering below tolerance voltages), etc.
If the machine is getting power to the motherboard, but won’t post, remove everything (including the cmos battery) but the CPU, one stick of RAM (ensure it’s in memory slot 1, inserting it two or three times to help clean oxides from the contacts), and the video card if so equipped (seat this two or three times as well). Remove the floppy and IDE data cables connectors from the motherboard end. Remove power to any disconnected devices.
Insert the cmos battery. Try to boot the machine. If it POSTs, power down and add your next RAM stick(s), one at a time with a power-up/boot between every add. Power down for every item addition.
IMPORTANT: Depending on your bios, you may have to enter the bios setup (http://www.d-a-l.com/faq/faq/23.html) and reset the NVRAM and/or “Update Configuration” switches at each boot.
If it doesn’t POST with the bare minimum components, the problem is one of those components. Depending on the age/use of the machine, the logical place to start would be the power supply (and video card). Testers for PS’s can be obtained for little money. After that, if you don’t have the equipment to test motherboards, CPU’s etc, or, a supply of extra compatable components laying around, it’s best to take it to a reputable repair shop for testing.
Next add the floppy data cable (align red/blue stripe/Pin 1 correctly) and power to the drive. Try to boot with a floppy boot disk. If successful, (power down) and add IDE #1, with master disk only connected to the data cable. Connect drive power cable. Boot without a floppy bootdisk this time. Because the bios was reset to factory defaults (battery removal) the disk should be automatically detected. If everything is OK, power down and add the slave device/cabling to IDE #1. Repeat the boot process.
Connect/test IDE #2 next, in the same manner, one device at a time. Get the IDE devices running first then go on to any plug in cards. Continue this way until you encounter the POST fail again. If you do, the last device is the cause. If you don’t, you’ve successfully cleaned/reseated all your connections and the machine should be OK unless there is an intermittent failing device.
