memory slots empty
I noticed the other day, that my late 2009 27" iMac only had 2GB of RAM displayed on the "About this Mac" splash screen. I clicked 'More Info' and discovered that, according to the system profiler memory tab, I had only one slot used and three slots empty.
As the Mac had shipped with 4GB of RAM, I was a little puzzled, so I took a look at the memory slots only to find the top two slots were used and the bottom two empty and not, as the memory tab on the system profiler suggested, that only one slot was being used.
I swapped the RAM from one slot to the other (top slots only) and I'm still being told that three slots are empty.
Does this indicate a faulty slot? Any thoughts?