Thanks cache. Any help is really welcome. As it happens, all drives/partitions are formatted NTFS. Yesterday, I took some advice of another tech. forum regarding trying to 'see' the ext. hdd whilst in Safe Mode. I did this and posted the following reply to that thread... it may shed some light on what the underlying problem has been. " Bris. Booted into safe mode. Powered up ext. hhd.. Immediately visible in Device Manager (under Disks and USB Mass Storage Device). Not visible in Disk Management and My Computer. Disks visible everywhere were Disk 0 (partitioned C: and E: (logical drive)) and Disk 1 (H: which is the card reader in an HP all-in-one printer etc. etc.). Went into Event Viewer>System Log- lot's of errors and warnings which were disk related (numbered 7, 11, 51). Rebooted to a standard start to obtain the internet connection to check out the error codes, and the ext. hdd, which had been left powered up between the safe mode session and reboot, was seen everywhere and instantly. The read/write light is off which is how it used to be on first install when it worked fine. It reads- Disk Management:- Disk 1 Basic 149.05GB NTFS On-line "LACIE" (G

Healthy, Device Manager:- WDC WD1600JB-00GVA0 USB Device (inc. an entry under USB Mass Storage Device) and in My Computer:- LACIE (G

. It would be very pleasing if this occurred on every reboot! From what I've described above, has anyone any ideas as to what the problem is/was. Oh, and thanks again Bris for resurrecting the thread." I'll now have to see whether it remains visible. Incidentally, I didn't turn on the hdd this morning so I don't yet know whether it's still visible.