Lets make it simple.
Start notepad and copy and paste the below in data:
REGEDIT4
[HKEY_LOCAL_MACHINE\SOFTWARE\NVIDIA Corporation\Global\NVTweak]
"CoolBits"=dword:00000003
Save the file as coolbits.reg. Click the file and it will merge the data for you without having to mess with registry keys.
Restart and then go to Display Properties-->Settings-->Advanced-->Geforce...-->Additional Properties-->Clock Settings (used to be Hardware Options).
Have fun!
<i>Its not fun AFTER you have fragged everyone.</i>
James