First you have to know the default voltage of the proce and then to do some tweaks and tricks. The main object is to increase the FSB of your choice and get it stable.
Here is what you have to do in BIOS:
AI Overclocking: manual
FSB Frequency: manual
PCIE Frequency: 100
DRAM Frequency: auto
DRAM Timing Control: auto
DRAM Static Read Control: disable
Transaction Booster: auto
CPU & PCIE Spread Spectrum: disable
CPU Voltage: to default
DRAM Voltage: 2.1
C1E Support: disable (can change back after OCed and got stabled)
Max CUPID Value Limit: disble
Vanderpool Tecnology: enadle
CPU TM Function: enable
Execute Disable Bit: enable
PECI: disable
Intel SpeedStep: disable or you can set the CMOS Ratio to 8
Q-Fan: disable
Now increase the FSB by going not more than 3-5 at a time, save your settings and successfully boot into your windows. If it refuses to boot into windows after a certain increase of FSB then increase your voltage by one noth only at a time untill you boot into the windows. Do this untill you have reached you required speed.
Atlast you have to do some tests for the windows to get stable. Download some softwares like Orthos, cpu-z, speed fan, coretemp which are absolutely free. Run orthos minimum for 8hrs to test the stability, run speedfan or coretemp to see the temps, cpu-z for veiwing system info, RAM, vcore(CPU volt). If orthos get unstable increase the vcore by 1 noth only and test again.
NOTE: donot let the CPU temp go above 60c, donot do anything with the RAMs for now. Need better CPU coolers to reduce the heat and better RAMs to OC more higher. Always see your HardWare Monitor in BIOS to get the actual vcore because vcore varies due to vdrop
I have reached 3.0GHz@1.312v though Vista is demanding more vcore than XP to get stable, with XP I have got 1.28~1.30V stable
, 28~31c ideal & 53~55c on load with Q-Fan option disabled