Technically speaking the CMOS (Complimentary Metal-Oxide Semiconductor) is the physical chip on the motherboard that stores information on the hardware configuration of your computer as well as the system date and time. CMOS is powered by a battery which looks a bit like a watch battery. Its CMOS that contains a firmware program called BIOS which performs four distinct functions.
1. It tests the computers main components by running its POST (Power On Self Test) program to make sure that they are all functioning properly. If not the POST will probably produce a series of beep codes.
2. The BIOS configures main components that are part of the motherboard or that are attached to it e.g. keyboard, mouse etc. This configuration role is decreasing all the time because modern operating systems are taking over more and more of these BIOS functions.
3. It boots the operating system from the hard disk drive or from a bootable floppy disk or CD/DVD at start up.
4. It provides access to some of the computers components and features, such as the keyboard, even when the operating system is running. In this way the BIOS provides an interface that lets hardware changes take place without having to make any changes to the operating system code. Windows 2000, XP and Vista only make a small number of calls to the BIOS because of their greater device management capabilities.
You should only flash the BIOS for a specific purpose, such as with an older PC where you need to use a particular piece of hardware. The only other reason to flash a BIOS is to fix a known BIOS bug that is well documented.
Before you even begin to think about re-flashing your BIOS check your computer's motherboard manual to find out how BIOS updates are installed. If you don't have a copy, download one from the motherboard manufacturer's website.
And don't forget to go into your BIOS and write down (or take a photo if you' have a camera) all of your settings. This is crucial because the "default" settings may not be the best option for your system, especially if you've already tweaked your BIOS and you do not remember anymore what tweaks you've applied.
Before re-flashing you should also try to install new drivers for the hardware you want to use, from the manufacturer's support website. If that fails to resolve your problems, you should carefully check all your BIOS settings. You might also try resetting the BIOS to its default settings.
If none of that resolves your problem, you may have to flash the BIOS. But you must take great care in doing this. Flashing a BIOS can go wrong and your system could be out of action until you can get a BIOS program restored or you purchase a new motherboard that has a working BIOS chip.
If the only option left to you is to flash the BIOS then here are the steps you must take.
The manual BIOS flashing procedure reprograms the BIOS chip on the motherboard, and is usually accomplished on a Windows 95/98/Me system by copying the downloaded flash utility and the new BIOS file to a floppy disk containing the three DOS system files that make it bootable. Most motherboard manufactures suggest that this procedure is also used for Windows 2000, XP and Vista (as long as you have a floppy drive attached to your PC.
There are three DOS files that make a floppy bootable; command.com, io.sys, and msdos.sys. These can be transferred to a floppy disk by typing the command sys a: at a C:\> prompt in DOS. Within Windows you can also double click My Computer, put a floppy disc in the drive and then right click the 3 1/2 Floppy (A:) and select Format. Select Create an MS-DOS start up disc and click Start. When the floppy disc is ready just delete the extra files leaving just command.com, io.sys, and msdos.sys on the disc. Now test the new start up disc to make sure it works.
You can then use your zip/unzip program to extract the new BIOS file and the utility that does the re-flashing to it, so that the boot floppy disk now has only five files on it.
Be sure to write down the name of the BIOS file to be installed and carefully follow any instructions about the BIOS file you downloaded.
Start by rebooting your PC, leaving the prepared floppy disc in the A: drive.
Type in the name of the flash program and then ENTER.
Follow the instructions to the letter! Abort the flash procedure if you are in any in doubt. It may also be wise to write down each step as the program runs through its menu.
Make sure when you get to the "save" old BIOS that you do save it. Make up an "old" BIOS name that you can remember and write it down, you may need it later.
When it's time to type in the name of the BIOS file to be burnt into the chip, type it in and then compare this to the written down name - make sure that there are no typing errors. Hit Enter. Be sure not to touch any keys, don't reboot, don't turn off the power. Wait for the update to complete.
When the message pops up that the BIOS flashing is done you will probably get a message saying that you can turn the PC's power off or reboot the PC. Its best just to wait for a few minutes to make sure the program isn't still writing to the BIOS chip. If all has gone well the updated BIOS has now been successfully installed.
If an error message occurs. Read it carefully. Something has gone wrong and you'll need to see if there's a way to re-flash at this point. Do not exit the flash program.
If the flash program is still running then this is the only time that you can re-flash without the BIOS chip working. Try reloading the old BIOS file that you saved. If you can't get the program to respond and there is no other way to reload the old BIOS. Turn off power and hope for a POST message when you power up your PC.
If all has gone well you should be facing a POST message when the PC starts up. Follow the POST instructions to enter CMOS and reset the BIOS settings to "default" if that's the best setting for your machine. Alternatively, check all of the values and make sure that they are correct. You may also want to have BIOS auto detect your IDE hard drive(s), to be safe.
Note re SATA Drives - Even if they are installed correctly, SATA drives may not appear at all in the BIOS depending on the manufacturer of the motherboard and the way that SATA support is implemented. This doesn't mean that they won't work, it's just that you can't confirm their existence without using Windows.
Carry on booting into Windows and check that everything is working, particularly your file and drive access.
If there's no POST message and the computer seems to be dead. Is there a "beep code"? If so, maybe you loaded the wrong BIOS and the computer can't find the video. Try to boot to "A" and see if you can re-flash the system. You should follow the list of steps that you wrote down earlier.
If you computer is totally dead you will need to spend some money and have someone re-flash the BIOS chip for you.
The above steps mainly apply to Windows 95, 98, Me and occasionally, Windows 2000.
Some motherboard manufacturers such as MSI, have an application that locates, downloads, and updates the BIOS automatically. MSI's application is called MSI Live Monitor, which can also update the motherboard's drivers and graphics drivers if the motherboard has an integrated graphics chip.
You can install the application from the CD that came with your MSI motherboard, or access it via the company's site. It is an automatic procedure that downloads an executable BIOS update to your hard disk drive, then reboots the computer and runs the executable file, which is programmed to perform the update.
You install MSI Live Monitor. When it is installed, the MSI Live Monitor icon appears on the Desktop. You double-click it to run the application. The Live BIOS and Live Driver tools locate the latest BIOS, driver, and firmware files. If you select them to be updated, they are then installed automatically. The Live Update application can be scheduled to look for updates on MSI's website.
Other manufacturers generally offer similar tools to help with BIOS updates especially for later operating systems including Windows 2000, XP and Vista.
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