How to make MBR of HDD as read only

Some times due to the virus attack or some other reason, the MBR of a computers’ hard drive goes corrupted or the information therein changes resulting a hard drive crash and data loss.
Will some one kindly tell me any method so that I can write protect the MBR to avoid HDD crash and resulting data loss.
Some BIOS’s have this feature that warns in such situation but what for the computers that do not have this type of bios?
We can avoid data loss by taking regular backup but at least re-installing all softwares can not be avoided by this.