The machine is an Intel Celeron 2.4ghz running windows xp home edition
The Motherboard is made by MSI and is model number MS 6787 version 2. there is a link to the specs and the manual here:
The motherboard has two 184 pin slots, and came fitted with one 512mb DDR stick (333Mhz-CL2.5). I am attempting to replace this with two 1Gb sticks. They were bought from Novatech, and are type PC2100, 266mhz, 2.5v DDR. I have consulted the motherboard manual and it lists PC2100, 2.5v as being compatible. One thing that I was struck by was that the manual mentions 266mhz speed ram, but not 333mhz, which seems odd seeing as that's what the machine came with.
We I installed the two 1gb sticks, the total ram displayed in both BIOS was only 1gb, suggesting that the system is only rating them as 512mb each. I have tried each stick individually, and in each case it shows 512mb (in both BIOS and in XP). They even work fine if used in conjunction with the old 512mb, yet, with any combination of the three of them I still only get 1gb. The manual for the motherboard states that it can support up to 2gb. I have updated my BIOS to the latest version, and reset BIOS to optimum settings, but with no joy.
I ran a program which was suggested on another forum, which checked the computer and displayed detailed systems information, but I can't for the life of me remember what it was called, other than that it started with a C and had three letters (and maybe a dash betwen two of them?) Anyway the significant point of this ramble was that this program showed my memory as 1.5gb (at the time I had one 1gb and the old 512mb stick installed). As this program can see that the memory is all present and correct, I think I can rule out the possibility that the chips have been programmed with the wrong capacity. So why can't BIOS or Windows see it?
Any ideas would be met with intense gratitude.
PS - I've tried to supply as much detail as I can, however I apologise if I've missed out anything really obvious.