E6400 2 4 ghz overclock

welshmousepk

Distinguished
do some research.

its not something you can do without being very sure you are doing it right.

obviously, you do not know what you are doing. so spend some time on google, read some guides and make sure you know enough to not break your system.

after that, if you still have some questions (more specific ones) come back here, and we will be happy to help.
 
System specs, especially motherboard, RAM and PSU?

This should be your first stop.
HOWTO: Overclock C2Q (Quads) and C2D (Duals) - Guide v1.6.1
http://www.tomshardware.com/forum/240001-29-howto-overclock-quads-duals-guide

Next stop should be a guide for your particular motherboard. Google is your friend.

If you have a Gigabyte motherboard, also look at this:
Shadow's Gigabyte motherboard OC guide:
http://www.tomshardware.co.uk/forum/page-245679_11_0.html
It's for an EP35-DS3L but all the Gigabyte Core2 BIOS's are similar.