Virus On motherboard

Well anything that can contain instructions that can be read by the computer can have a virus in it, this includes the NVRAM (or Programmable ROM) normally associated with the BIOS.  These virus's are extremely rare and very hard to implement while maintaining the stability of the BIOS instruction set.  

There are also extremely easy to eradicate as all you need to do is reprogram the BIOS of your motherboard.  And not very effective for use as targeting any operating system specific exploits because there is no guarantee that the OS installed on the computer is the OS your virus is targeting.

-saige-

The most common place a virus is found is in software as either part of your operating system or some sort of trojan horse application. Almost all viruses live in RAM while the computer is turned on since no program can do anything without a RAM component. However, since RAM is volatile it is completely erased as soon as the computer is shut down.

Rootkit viruses can live on the hard disk below the operating system level, even at the master boot record (MBR) level. These viruses are harder to detect and simply reinstalling the operating system doesn't eradicate them. To remove a virus from the MBR you need to perform a full hard drive format and repartition the drive.

There are known cases of BIOS viruses (https://www.webroot.com/blog/2011/09/13/mebromi-the-first-bios-rootkit-in-the-wild/) but they are not common. Those are the most persistent and hardest to remove but certainly not impossible.

Short answer, viruses can live in BIOS or on the hard drive. All viruses, regardless of how they are stored, will be in RAM at some point. That is how they are detected by antivirus programs.

Hi,
well, all antivirus can scan RAM nowadays IMHO.
But for motherboard, there is nothing or almost nothing to scan...
Answer woould be drives, hdd or ssd, and RAM, that's the main 99.9999% majority of virus issues.
Maybe I miss something, we'll see if other experts got some ideas on this.

yodaa, is your question a general one for info, or do you have a specific problem?
if so, post it