Go into the BIOS & check that the CPU FSB is at 166Mhz - change to this if it isn't, save & exit the BIOS.
If no joy with above, try clearing the CMOS via the jumper method or remove the CMOS battery for a while & replace - shut down PC & disconnect power cord before doing this.
If you're not sure about the jumper method, the manual should tell you how click here. IMP: Replace jumper to original position before powering on again. G