Right, last bit of fiddling: Windows XP 32 bit displays the same issue, as does a different power supply. 2200's previous owner has confirmed the card has been used in a 'sleeping' system before. I've contacted the retailer so will see what they say....

The thing is, hibernate works fine, and it comes out of hibernate to do a recording no problem. Waking up to record while I'm away is the main reason I was interested in sleep, otherwise I'd just switch it on and off once a day for normal use. So I could live with it.