I recently installed a USB 2.0 external hard drive via a USB 2.0 PCI card (with a hub plugged in) in my Dell Dimension XPS R450 computer (running XP Professional), and partitioned it into two logical drives. It functions fine in either partition -- except that neither partition shows up in Windows Explorer or in My Computer, which makes it inconvenient to navigate to.

In Device Manager it IS present, showing up under "Disk Drives" as a USB Device, and under USB Controllers there is a line "USB Mass Storage Device" which appears twice, no doubt because of the drive's partition into two logical drives. The drive and its two partitions also shows up in Control Panel: Administrative Tools: Computer Management: Disk Management. Working from those listings I have put a shortcut to each logical drive on the desktop, where they give ready access to the drive's two partitions and make it possible to move files to and from each. But just as My Computer fails to register the drive and its partitions, other programs (such as backup software) do not recognize it/them, which makes it tricky to use the drive for the main purpose I got it for, namely as a destination for backups.

Is there some way that I can induce My Computer to notice the drive and its partitions? I am grateful for any ideas folks might have about this.

LST

Try changing the drive letter/s under Disk Management.

Right click the drive (partition) and choose: Change Drive Letter and Paths...

Just choose any unused letter/s.

Thanks, Jephree, for a good suggestion, though it didn't work. In Disk Management I changed the drive letters for the two USB hard disk partitions from I and J to K and L, and rebooted, but the drive/partitions still were absent from Explorer and My Computer. Then I changed the letters back and rebooted, with the same result.

I didn't mention earlier that part of the strangeness is that, in Windows Explorer, even though the I and J partitions are missing in Folder View as I said, I can type in "i:\" or "j;\" in the address box and get immediately taken there. Obviously part of the operating system knows about the USB hard drive, though only part of it.

LST

Friends, I found the source of the trouble. Tweak UI has a "drives" tab, which one can use to hide logical drives: only the drive-letters that are checked are shown. I never did anything on this page. It had apparently picked up its distribution of check-marks (correct at the time and until recently) from My Computer when it was installed, without adding check-marks for I and J when I recently installed my USB hard drive, so that I and J were unchecked. Checking them immediately resulted in their appearance in My Computer and Windows Explorer in the way one would expect.

This is perhaps a way in which Tweak UI needs to be tweaked.

LST

Glad you figured it out and thanks for the tip!

Hopefully this will help others in the future.

Thanks for letting us know! I will remember it.