When the computer is turned on, the processor address to the ROM chip, which recorded BIOS code - the original program download.
BIOS initiates the start of POST - self test of the computer hardware.
Upon successful completion of the test control is transferred to the operating system.
If the BIOS does not start, this indicates a problem with the system unit components.
Problems with power supply
Over time, even a good power supply losesperformance, and its characteristics are no longer always apply. For example, they may swell or explode the capacitors on its motherboard. Visually, it looks like a convex end surface or a small amount of gel around the capacitor electrodes. Such damage is easy to detect and replace the damaged item. However, even in the healthy-looking capacitors dry out the electrolyte, and the power supply is not working properly. For example, there is a "cold start" of the system unit, i.e. require several reboots to the power supply elements warmed up, and the computer is on. If the power is turned on the BIOS does not start, try replacing the power supply unit to a known-good.
Problems with the ROM
ROM chip is powered by a round battery,next to it on the motherboard. Nominal voltage of the battery should be 3 V. If it is reduced to 2.7 V, could be in trouble. Replace the battery with a new one, remembering how it should be installed.
Problems can also be caused by changes in theBIOS settings. In this case, will reset to the default set. Disconnect the computer from the network by pulling the plug out of the socket and carefully remove the battery. Jumper electrodes with a screwdriver in the slot where the battery has been installed, and hold for 30 seconds.
Problems with other components
Unplug your computer and disconnect frommotherboard hard drives, CD and DVD drives, remove the RAM module from the slot, and all expansion cards. Staying have only the power supply and the CPU. Turn on the computer. If the speaker emits signals, hence, the BIOS is started and with motherboard and processor, all right. Start alternately connected to the motherboard, RAM, graphics card, hard disk drives, etc. Previously it would be very useful to wipe pads video card and RAM modules of the normal school eraser. Of course, before each connecting computer must be disconnected from the mains. If after connecting any element BIOS will not start, you have found the culprit problems.
The problems with the motherboard and processor
If the system unit does not start in the configurationmotherboard + CPU + power supply, carefully inspect the motherboard capacitors for swollen - it is the most common problem.
It did not work on the power buttonthe front panel of the system unit. Find the connectors on the motherboard, to which it is connected (usually designated by Power or PWR). Disconnect button on the motherboard and Jumper connectors screwdriver. If the system unit has started, it is necessary to change the button.
Remove the processor heat sink and cooler placeon his finger and turn on the computer. Hold the processor heat sink under voltage can be no more than 4 seconds. If the processor begins to warm up, then it is OK. Immediately turn off the power by pulling the power cord.
Lubricate the sole radiator fresh thermal paste,erasing previously dried cotton swab dipped in alcohol. Install the heatsink and the CPU cooler, turn on the computer and see if the fan is running.
Check for heating of the north and south bridge (2 large chips, perhaps with installed radiators, on the motherboard). If overheating occurs, it is best to contact the service.