I have pretty much this problem with my newly built replica. I've just scribbled down all of the suggestions in this thread which I will go and try in a second however. I suspect that the issue may be the keyboard - it is one of the silly ones with multimedia keys (it's hard to get a vanilla ps/2 keyboard these days it'd seem).
When I power on and reset I see this
\
@
which I gather is correct.
Also the power switch doesn't really seem to do anything. I'm using USB power and as soon as I plug in the cable the board powers on regardless of the position of the switch. I've checked the switch for solder bridges etc and it all seems fine; I guess it doesn't really matter but it does seem somewhat bizarre.
Another thing I ought to mention (more regarding the keyboard) is that I had a slightly faulty iron which I didn't notice until it had managed to burn the board slightly in one place. I checked the track which is nearby to make sure it is still in tact and it seems to be (I only have a multimeter however) and then the iron I bought to replace that was the single most worthless bit of kit I've ever used (the tip melted and a tiny bit dripped onto the PCB amazingly) and didn't notice that until it also had burnt the board very slightly, although it is on the bottom in an area with no tracks so I'm not worried about it. I thought this would be worht mentioning in case it could be an issue, but as I said I checked everything over when I realised what happened and it all seems ok to me. That'll teach me to buy Draper products; I should have known better.
Anyway, thanks in advance for any help,
Joe