The molex power connector was for a PATA drive that kept going invisible, the SATA drive has one of those nice thin ones doesn't it ? Would just do the check disk repair thing and get it to correct errors (and reboot, and wait and wait...). Ok, change disk if it happens again anytime soon otherwise just backup and plough merrily on. Have had bad sectors on two machines and disks carried on without anything terminal happening (however past performance isn't a guide for the future, E&OE etc).