i have a spare hard drive and i dicided to buy a caddy. After i enstalled it the drive appears in my computer for 10 seconds then disapears and a message saying drive has failed try reinstalling to correct problem. When i check the drive its says its ok and is working properly. If i put the drive inside the computer and connect direct the bios pick it up and it runs fine. The only reason i want to use the exturnal one is because i have serveral drives and like to keep my work seperate and can take it out quickly. If anyone has a way round this i would be greatful, i'm running xp pro on a intel dual core processer.

If the drive is a PATA the jumper may be set wrong. You need either set to Master alone or NO jumper installed. You are using external power too?

I 'm using aseperate power suply and the drive is set to master I can here the drive and when i put power to the drive the message reads found new hardware then your hardware is installed and ready for use but no icon appears in my computer. Thanks Andy

Device Manager may just be finding the Enclosure and not the actual hard drive. If the drive is not formatted it will not be assigned a drive letter or appear in My Computer. Look in Disk Management to see if the drive shows there. If so, you can partition and format from there.