XPPro machine E8400,Gygabite EP45-DS3L,Award BIOS F7,4GB RAM (3), monitor Acer X193W,Seagate ST3500630AS. I am getting mad with external Hard disks lately with this machine. 1-The only one working perfectly is a Lacie 300GB which six months ago died with iron clangs and noises when partitioned in 3 but resurrected when I decided to format and leave just one partition.It now works ok (I gave letter Y)and I have no problems at all imaging/restoring from it. Problems came when I decided I had to buy another to store more images: 2-bought a cheap Trekkstor 160GB (thought smaller less chances of malfunctions...).this one is recognised,given letter Z,everything is fine,but if you attempt to restore an image from it it wont boot after Paragon/TrueImage completes ,you have to manually reboot.....which is not exactly the best thing. 3A-bought a 640GB Maxtor: after 2 days it died. 3B-promptly changed by vendor, it is recognised and poses no problem booting,but Paragon warns of assorted I/O problems not only in this machine but also in another one. 4-I finally decided that ,as Lacie works,I had to buy another one so i got a 500GB Lacie ext HD. this one was properly installed,gave it letter X, formatted by the native software and finally by my HDManager, it is recognised perfectly,but to my dismay if I leave it on and reboot IT KEEPS REBOOTING FOREVER after 2-3 attempts from my machine to complete boot I simply switch it off by unplugging it. the only physical difference with my other working Lacie300 is that it lacks the switch on-off button,which the Porsche Lacie 300GB has. Both are primary devices and both are optimised for removal. This HD ,when plugged to my notebook also XPPro and running similar progs, presents NO trouble whatsoever and works like a charm........ I went into my BIOS searching for clues,but found none to my little knowledge.BIOS CMOS setup utility is set like this: 1-ChM. : ST3500630AS 2 Bootable Add-in Cards Hard Disk Boot Priority [press enter] First Boot Device CDROM Second Boot Device HardDisk Third Boot Device Disabled I already tried changing USB,plugs locations ,no UPS,no surge protectors,anything to no avail. In order to prevent this Lacie500 to mess my boot and behave properly I am thinking of removing the 'primary' qualification and make it a non bootable one,either extended/logical. Will this help? Is there anything I can do? Anyone had similar trials or has suggestions?