Malware

Can you be more specific?
What message do you get that you think virus gets loaded to MBR?

From your descriptions, I am not sure if it is the virus problem.
Many older MB including KT4 has a setting in the BIOS that allows a user to enable or disable Boot Sector Virus Protection. If it is enabled, it will give a warning of boot sector writing or rewriting when Windows installation starts. BIOS just does not know whether a virus or Windows installation causing it. Either you have to ignore the warning or simply disable the setting.

If you must do the BIOS flash, do as MSI recommends; NEVER flash the BIOS from a floppy.
Boot from a Windows 98 Startup disk, create a folder in C:, copy BIOS files to the folder, and then run the flash command in the folder.

1. Check your BIOS for BIOS FLASH PROTECTION and make sure it's DISABLED, some motherboards have this function.
For Example:
K7N420 Pro (MS-6373) ? BIOS setup/Integrated Peripherals/BIOS Protect/Disabled
2. Find the exact model motherboard you have.
a. First check inside the motherboard bios, some motherboards, like the MS-7030, show the bios version in the bios, under Standard CMOS Features.
b. Open your case and look for the MS-XXXX number on the motherboard, using located between the PCI slots, also check the version number as well. (Some motherboards like the MS-6390 have different versions, in which each version uses a different bios)
c. Boot up your system & take a look at the top left screen during POST, you should see something like ?W6390VMS v2.6 092903? This means the board is MS-6390 with BIOS version 2.6
Hint: Many systems run to fast, that you will not be able to see this line, you can either press ?PAUSE? key or you can disable the ?Quick Boot? & ?Full Screen Logo? options in the BIOS.
3. Download the BIOS that match your motherboard model and version number. BIOS's can be found at this link, which are separated by CPU socket type (socket 775, socket 478, socket 754, socket A, and archives)
4. Extract the BIOS that you have downloaded by double click it and extract it to a blank formatted floppy disk.
5. Boot the system with a bootable floppy disk
a. A Windows 98/ME startup disk can be used
b. Or you can create an MS-DOS startup disk under Windows XP, to create an MS-DOS startup disk under Windows XP, right click on the 3 ? floppy drive icon under my computer and select format. On the format dialog box, check the box next to ?Create MS-DOS startup disk? and then click the start button to make a MS-DOS startup disk.
6 Once you boot off of the bootable floppy disk, replace the bootable floppy disk with the floppy disk containing the bios files.
7. At the A prompt, you will type in the following command
a. A:\FLASHUTILITY BIOSFILE.VER
b. The flash utility will be the .EXE file included in the BIOS you downloaded. For example: ADSFI712.EXE = BIOS FLASH UTILITY
c. The BIOS file will end with the version number you downloaded. For example:
A6728ims.210 = BIOS file version 2.10
8. To update the BIOS using the example above you would type the following command.
a. A:\ADSFI712 A6728ims.210, then push the enter key.
b. Follow the onscreen prompts to update the BIOS.
9. DO NOT TURN OFF THE POWER or RESET/REBOOT the SYSTEM before the BIOS update is completed, stopping the BIOS UPATE before it is completed will cause the system to become non-functional.
10. Reboot the system once the bios update has been completed.

The only thing that may be a bit hard to follow is this part

A:\FLASHUTILITY BIOSFILE.VER

But it's really quite simple you need to insert the Bios Flash Utility where it says Flash Utility and the BIOS File where it says BIOS.Ver You will have extracted both of these after you downloaded the BIOS.

However I'm wondering why you think that you have a BIOS Virus as while this is possible that are not overly common and as th above poster has already said if you have the Boot Virus Scanner turned on it will quite often pick up a False Positive so it's better to turn off in BIOS.

But if you want to flash the BIOS I always have the computer connected to a UPS just in case of a Power Spike or Failure while the Flashing Utility is being run as that will cripple the M'Board if it happens.

Similarly you can buy a new BIOS Chip for very little from this place

http://tinyurl.com/37qjt8

I always buy new BIOS Chips for any Mission Critical Servers instead of running the risk of having a BIOS Flash Fail and have something critical down till a new BIOS Chip can be got. I've always had excellent service from this company and never a single problem but you do have to specify exactly which BIOS Chip that you want and provide the necessary details so that they can send you the correct Chip. But I generally have a replacement Chip within 7 days from order which is very good considering that I'm in AU and this Chip is coming from the US.

Col

TRY THE CMOS RESET JUMPER.There are virus that reside in the BIOS.A hacker on the Internet can place a virus in your BIOS ruining your computer.If you disagree with them in a forum then your computer gets wrecked!