A method of error detection during a booting process of a computer system includes: for each of setting variables of a BIOS program, determining whether or not a respective one of stored values corresponding to the setting variable is in a respective one of value ranges corresponding to the setting variable according to a variable range comparison table; and when it is determined that for at least one of the setting variables, the stored value corresponding thereto is not in the respective one of the value ranges, updating, according to a variable definition file, the at least one of the setting variables using one of preset default values corresponding to the at least one of the setting variables.