Computer and Software Support


No Post causes

Stands for Power On Self Test. This happens before the system is turned over to the hard drive, CD-ROM or Floppy when you turn the system on.

To troubleshoot a no post click here.

The system goes through two stages. the first stage is P.O.S.T.. The second stage is Boot.

When you push the power button, it starts the P.O.S.T and it consists of...

  • Turns the power on the power supply
  •  Enables the video
  • Enables the CPU to communicate with the motherboard and BIOS
  • Checks the memory

 

When P.O.S.T. finishes, the Boot begins

  • System looks for a bootable device which can consist of a Floppy, Hard drive, CD-ROM, network or other bootable means.
  • Once it finds a bootable device, it determines if the boot device has boot instructions on it. The order of the boot sequence depends on what boot devices are installed and the order setup up in the BIOS.
  • It reads the boot instructions and proceeds to boot per the instructions. 

 

Different scenarios in issues with system turning on

  • No video can be a no P.O.S.T. issue but not always the case. System still can P.O.S.T. and Boot to a bootable device such as the hard drive.
  • No P.O.S.T. is considered when the system will not come on or get past the BIOS screen.
  • No Boot is considered when the system cannot find a bootable device or unable to boot to a bootable device. 

 

There is numerous possible causes of no Boot, No P.O.S.T., freezes, hangs, or error situation

  • Storm can cause software corruption, a no boot, or a no P.O.S.T. situation.
  • Power surges can cause software corruption, a no boot, or a no P.O.S.T. situation.
  • Incompatible devices
  • Malfunctioning device
  • Loose connection - reseating a device usually fixes this issue. (see below on information on loose connections)
  • Bad hardware
  • Software - will not cause no P.O.S.T. but can cause No Boot.
  • Virus - rarely causes no P.O.S.T. but can cause No Boot.
  • Driver or software corruption - cause errors or No Boot.
  • Improper connection - can cause No P.O.S.T. or No Boot
  • Plugging or unplugging devices while system is on
  • Improper shutdowns

 

Loose Connections

Computers get hot and they get cold. Parts expand and constrict. Even though a part may appear to be seated properly, it may need to be reseated. Also the connectors can get oxidized and by reseating the device, this can clean and reseat the connection and in turn fixing the issue.

 

Surge Protectors

Surge protectors will not always prevent the system from against surges. They do protect the system but a surge or a storm can still harm the system. It is only a tool. Like a human can still get the flu after getting the flu shot, a system can still be hit by a storm.  Also surge protectors weaken every time they take a hit. You should replace them periodically. The cheaper ones needs to be replaced more often then the more expensive ones but all of them needs to be replaced periodically. There is no set interval to replace the protectors. Depends on how often they take a hit and how good they are.

 

Phone lines and Cable modems

Surges can come through the phone line or cable modem line so in a storm, you should disconnect them or at least have them in a surge protector (not 100% safe but better than nothing if you leave it connected during a storm)

 

No P.O.S.T. Complications

Problem with a no P.O.S.T. issue, is that unless you can see damage, you do not know if the no post was caused by a storm, surge, or a device just failed. If a device failed, then more and likely just that part failed and other parts will be ok, unless it shorted something else out when it died.

If the No P.O.S.T. was caused by a surge or storm, it can cause the following scenarios

  • Only one part is damaged and replacing that one part will fix the issue.
  • More than one part is damaged causing to replace multiple parts
  • Damaged some parts but weakens other parts. You replace the damaged parts and system works for a few days or a few weeks and then the weakened parts fails. (no way to detect if a part has been weakened)
  • Trying parts in a known good system can be hazardous to that system. If that part is shorted, it could damage the other system. Same goes with putting it back in the original system.

 

Boot devices and PCI cards

During a No P.O.S.T. situation, the condition of a boot device (such as hard drive, zip, CD-ROM) and PCI cards cannot be determined without trying them in another computer or trying it in this computer after the No P.O.S.T. is fixed. That is safe to do if the part is OK or just broken, but if the part has a short in it, it can take out another device. Putting the device back in the computer after a No P.O.S.T. can take out the system again.

When you re-install parts into a system that had a failure, install them one piece at a time till everything is installed. If the system dies or gives a problem, than the last part installed probably caused the issue.