When will the misery end? Initially, I only bought 2GB of memory for my x64 workstation. But I intended to add two more from day one, and today was the day - two additional Kingston KVR400X64C3A/1G DDR-400 modules were delivered to my doorstep. So in theory 4 modules would yield 4GB of memory.

Not so fast, Buster. Exactly. After finding out the hard way (blue screen and various other sorts of lock-ups), it looks suspiciously like the ASUS A8N-SLI Premium does not like four DDR-400 modules! (the ValueRAM site hints at this, and there are discussion threads too) that pretty much takes the biscuit.