Slightly confused here. Its the first I have gone beyond XP and have installed Window's 7 and have installed 6GB Gskill ram but when I go itno system within the control panel it says I only have 2ram
Do you have your RAM in the right slots? If this is your first foray into triple-channel memory, check that they're all in slots that are the same colour on the P6TD; you also have to start with a specific colour. (I've got a V1 and they're in the orange slots, IIRC.) Otherwise, yeah - what version of 7 are you running?
Odd, have you got all the windows 7 updates? by the way, typo in your signature specs. "HIS 5879 GFX card"
Very very common problem with 1366 set ups sadly, they are fussy about memory. http://www.google.co.uk/search?hl=en&source=hp&q=4gb+p6t+&meta=&aq=f&oq=
Load the XMP Profile, does that have any effect? I have the same motherboard and in experimenting I found that it 'lost' a stick if I tightened the timings too much or had insufficient QPI voltage (I have to run a QPI of 1.53125v to get mine to run at 2000MHz). Also try running MemTest86.