Do you mean ICH7? It consists of many

Do you mean ICH7? It consists of many blocks and any of them could be damaged. Than approaches to determine misfunction with VOM will be very different. The most easy for the beginning is just measuring voltage drop (with multimeter in "--|>|--" mode) from power supplying rails used by SB (can be found in schematic diagram) to the ground and comparing to those of functional mobo. They should not be orders of magnitude lower. But practically this method is rather useless. Note, that very frequent situation seen when the SB is damaged is its abnormal temperature observed in stand-by mode or on running MB. Frequently, mobos with defected SB can demonstrate no responce to pressing PW_ON switch, read description of RTC signals block, also SLP_S3# and SLP_S5# power management signals in ICH7 datasheet