1. Externally powered drive.
2. Other USB-port(s)
3. Powered hub in between
4. This drive on another PC.
Report your findings.
I own a Dell Dimension Desktop with Windows XP Professional SP3. Recently I added an external USB 2 Hard Drive. The hard drive was detected automatically and drive letters assigned automatically. I could see the hard drive in "My Computer" and "Device Manager." The external hard drive does not have any external/additional power supply. Both my internal and external hard drives are NTFS formatted. Since I intend to use the external hard drive as an additional disk drive I let it be plugged in permanently.
However whenever i re-start my PC, the external hard drive does not show up in "My Computer" explorer. But the drive is detected in Device Manager, and as an uninitialized disk drive in Disk Management service module of "My Computer." If I unplug the hard drive from the USB port and re-plug it it is automatically detected in my computer and drive letters also assigned automatically. I then shows up correctly in "Disk management" service module also, along with all logical partitions.
What's wrong?? Why does it not show up everytime i reboot?