Thanks for the support guys. Alain, your experience sounds particularly painful.
What were you doing actually Mani ? (I know, but why ?)
I was trying to 'clear the memory'. Switching the PC off didn't seem to work - as soon as I booted it up again, I would get the 'low memory' warnings coming up again. I tried unplugging the PC and leaving it for a few minutes before booting up again. Exactly the same thing. Then I thought if I physically remove and replace the DIMMs, the RAM would have to have been cleared.
Strangely, when I ran 'Performance Checker' (before I broke things totally), it was showing me very low memory usage. And yet I couldn't start any application (including XX)... due to apparently low memory.
I totally take the blame for screwing my mobo up. But there was something really strange going on before I did this.
Mani.