How to overclock amd phenom ii x6 1055t to 4 ghz

Hello,
My system is amd phenom ii x6 1055t
4gb kingston ddr3 Ram
500watt Cooler master
Mobo: Asus M4A78LT-M

I have overclocked upto 3.6ghz
but now i want to overclock cpu to 4 ghz
i have set frequencies but overclocke failed

i have set
286 x 14
7x multiplier
1400mhz ht
cpu voltage 1.42
(i have increase fsb five digits)
So please is there any body to tell me about overclocking failed
so please help me