Old Time PC motherboard

I have an old Time Pc (approx 1999) with a MSI 5191 motherboard. I have had problems from the start, but tech support (costing ?399!!) was useless. It has been very tempremental, and often will not boot up. After finding that removing the case and pushing the motherboard down, hovering it out, and generally fiddling with wires, it will eventually reboot. However, now this does not work. The power supply is fine. I think it is a loose connection somewhere. I need a wiring diagram for the motherboard. Does anyone know where I can find one?