First of all everyone who responded to you knows this but didn't explained to you. The frequency of a cpu is obtained by the following equation BCLK x CPU Multiplier = Frequency. To obtain 4.2 Ghz it would be 100 Mhz (base BCLK) x 42(multiplier) = 4200 Mhz (4.2Ghz). To set it on 0 it means the cpu will have 0 x 42 = 0 (anything multiplied by 0 is 0). It is not possible to have 0 Base Clock or BCLK how you know it. The default BCLK non-overclock is 100 so your BCLK IS NOT OVERCLOCKED in technical words it is the standard base clock (default one), anything over 100 BCLK is considered overclock. Your problem is elsewhere, maybe cpu cooler is not properly installed or the airflow in the case is not good enough but one thing should be clear...