Q6600 P5N-D won't overclock past 2.65GHz?

Here's some more info:

Memory: 3x 1GB 800MHz 4,4,4,12, 1x 2GB 800MHz 5,5,5,12 (bios timings are set to 5,5,5,12)
Processor: Q6600 G0 revision, 2.4 stock
Motherboard: P5N-D, running latest bios version

My problem is I simply cannot get the FSB to anything greater than 295 (linked with 3:2 multiplier, 786MHz ram clock). I've tried upping the core voltage into the 1.3-1.45v region, but i still get a blue screen with some generic hardware malfunction message before i even make it to desktop. Can anyone explain this? I've seen most people with this processor getting theirs to 3GHz with ease, and 3.6 with a bit of fine tuning.

One other strange thing to note is before the bios flash when i was running the 203 bios version, whenever i tried to turn off the virtualisation enable setting or whatever it's called the pc would instantly turn off as i saved the bios, then wouldnt turn back on until i reset the cmos manually. However i havent tested this with the new bios i just put on, as to reset it involves taking the graphics card out and some serious case shuffling, something id rather not do unless absolutely required.

Thanks in advance guys

/edit

oh also I should add, i'm aware running my memory as one dual channel two single channels is inefficient, it's just down to crucial sending me a 2gb stick instead of 1gb when I RMA'd it, which I am trying to get sorted soon. I'm hoping this shouldnt affect overclocking my cpu too much?

have you tried disabling intel speed step
also what multi are you running
for a 3.0ghz you should be using 333 fsb x 9 multi
im running 400 fsb x 9 multi giving me 3.6ghz

Might be your RAM holding you back...DDR2? or DDR3?

You should be able to switch FSB from 266 to 333 for an automatic 3.0ghz...no other changes.