Thanks Spannersatcx, I'd found that and tried it (and every combination of it) but it still doesn't work. I've now got C drive primary master, with second HD as slave, DVD as secondary master with CD-R as slave, all is still exactly as before.
Any more suggestions? I'm not sure if I have a problem with PowerDVD, Win Xp or the DVD itself. I searched the Powerdvd site but they don't mention the error, I've found a few queries on bulletin boards but no answers. I've left a question on the Powerdvd tech support site.
Any BIOS tweaks I should try? everything seems to be set on auto.
Thanks and happy new year.