pc crashes after overclocking

[MiNxYyY]

overclocked my Q6600 from 2.4 to 3.0,when i exit bios after saving,my pc crashes and restarts 4times before its loaded into windows,and now its stuck at 2.4,bios is showing multi = x9 and FSB = 333,voltage core is 1.3000,and crashes..

any ideas why this happens?

 

[MiNxYyY]

sometimes it loads ok,sometimes it crashes.. should i go for 2.8 rather than 3.0?

 

[MiNxYyY]

il try and take a screenshot of my bios