1024mb detected 1023 usable

[Pygmy_Shrew]

Hi guys I'm researching a blue screen problem i've got, usually it occurs when stressing the system out e.g. moving a file, listening to music, generally multitasking.

This is a long one but please bare with me, I'd just like to verify my suspicions.

I've since removed 1 of my 1gb sticks of memory, its some crappy Corsair Value Select and ive not had any blue screens since HOWEVER I have had different 2gb sticks in before and the blue screens happened then too so Im thinking its not ram its mobo?

I say this because the bios and bootup has discrepencies, apparently 1mb of any RAM stick I put in is not usable? If I put 2048 in then 2047 is not usable?

A lot of the blue screen errors relate to page file problems (addressing) some hint towards memory addressing.

So my question is to you does this sound like a mobo fault where for some reason addressing isnt catered for on 2gb or more or ram hence the blue screens during heavy load?

Edit:
Intel Core 2 Duo 6600 2.4Ghz
1gb Corsair Value Select @ 667mhz (removed 1gb for testing)
320gb SATA HD
1GB 7950 GeForce
Soundblaster X-Fi XtremeMusic
Asus P5NSLI Mobo