I have a 1 TB hard drive split in 4 partitions. When plugging in the HDD into my usual machine, the usb icon in the taskbar usually shows the 4 partitions as "subs" under the "Transcend Disk Drive" heading.
On another computer, the usb icon in the taskbar only showed the "Transcend Disk Drive" heading but not the partitions. Additionally there were no disk drives displayed in the "My Computer" window.
To get the HDD to show up, I ran the Disk Management window via the Microsoft Management Console (run mmc.exe & click "Disk Management"); there, a 1 TB "Disk1" was showing as "offline". All that remained to be done was to right-click on the "Disk1" heading and click online.
The different partitions then became visible on the taskbar(via the usb icon) and also in the "My Computer" window.
EDIT:
The reverse process can be used to remove a HDD when a "safely remove" via the taskbar fails. Simply make the disk "offline" and unplug.
2Does the hard drive have an external power supply or is it USB powered? Is this a laptop or a desktop? And are you connecting using a USB hub? Also, has this hard drive ever worked with this machine before? – David Schwartz – 2012-08-09T11:40:30.953