It is normal for these to populate the MY COMPUTER area. If you have card readers, these will show as removable disk. Now, with that said, if you want to change the drive letter, you can do so under the disk management console within the administrative tools -> computer management found in your system's control panel. Right click a drive and choose change drive letter. That simple. Leave a few empty between the removable disks and your hard drive(s) / media drive(s) so that any newly plugged in USB or other drives will acquire a higher drive letter. But this really doesnt matter to be honest with you. It is just how windows manages the drives.
You will not see drive letters in device manager right away unless an actual media card is inserted and you go into the device's properties. To see a drive letter in device manager, go under DISK DRIVES and expand the list. right click properties for each reader (you should recognize them by name)...and go to its VOLUMES tab Click on POPULATE at the bottom ... and if a card is inserted it will list it at the bottom and its corresponding drive letter. But you dont need to do this. You could manually remove the card reader(s) if you want by clicking on the device in device manager and choosing uninstall. But again, no need. Windows will reinstall these and assign a drive letter again, unless you choose disable instead of uninstall. But then the drives wont function at all until restored as active...
If you are woried about drive letters, change them as discussed. Hope this helps!
Edited by jay_man, 10 February 2010 - 10:45 PM.