The only thing I can think of is look through your system BIOS and see if there is an option to disable a block or stick of RAM. It's the only thing, aside from defective hardware, that would prevent the BIOS from 'seeing' the extra RAM.
One last thought would be to run memtest86 and see if it says anything different. It's possible that the slot is still damaged to a degree where the RAM is unusable but CPU-Z can still read the SPD information to properly identify the RAM. Memtest may be able to shed some light on it.
OK this is a weird one. I have an Abit A-20 mobo. It has 2 memory slots and is capable of a max. of 2 GB RAM. Ever since I built this computer abotu 2 yrs. ago, it has run with a single memory stick in slot 1 - a 256 MB DDR-SDRAM Corsair PC2700, part # VS256MB333. As you can see, this systems runs a 333 MHz bus with a 166 MHz FSB.
Now here's the trouble. I bought an EXACT COPY of the memory stick, another Corsair PC 2700 part # VS256MB333. Same stick, same size & type, same brand. I put it in slot 2 and the computer doesn't even see it. I swap the sticks. New stick in slot 1 and old stick in slot 2. Same problem. Computer (BIOS and Windows) only see the memory in slot 1.
Any ideas? Please help!
So you think maybe slot 2 is bad? Guess again. I bring up a nifty utility called CPU-Z that shows detailed info. about the CPU and memory and CPU-Z sees 512 MB RAM and it sees BOTH sticks individually. CPU-Z allows you to see what's in each slot and for slot 1 - there it is. Slot 2 - the stick is there as well.
So obviously the slot works and so does the new stick. I have software that can see both memory sticks but neither the BIOS nor Windows (XP Pro) can see the second one. This is very puzzling.