Your flash drive might not have a drive letter
Type the following into the Start Menu, and hit Enter:diskmgmt.msc
Maximize this Disk Management window, and look for something like "Disk 1" that is smaller than your hard drive (disk 0). The size should be listed.
Notice how I have a drive letter G: for this flash drive:
And notice how this one has no drive letter:
In the second image, this flash drive will not show up under Computer because no drive letter is assigned to it.
To add a drive letter, right-click the flash drive's partition:
and click "Change Drive Letter and Paths".
Next, click Add:
And choose the drive letter you want to use (I'm using F):
Now my flash drive shows up in Computer with the drive letter F.
Let me know if this solves your problem or not.
Edited by keyboardNinja, 29 March 2011 - 01:20 AM.