I was setting up a new PC with Vista. Initially it detected a card in its SD 
card reader (*) and displayed it as an additional drive. But then I changed 
the drive letter in Control Panel | Admin Tools | Computer Management | Disk 
Management to avoid a clash with a pen drive which had to be on a specific 
drive letter in order for SyncToy to back up to it. The change of drive 
letter was relected in Windows Explorer (the "Computer" link on the Start 
menu), but then after I removed and replaced the card, the drive was no 
longer detected.

There was no bing-bong as a USB or SD device is plugged in, nothing showed 
up in Device Manager | Disks or in Disk Management and the drive was not 
accessible (under either its initial or modified letter) from a DOS prompt.

Any suggestions what happened and how to make Windows detect when the card 
is inserted.


* The card was actually a Memory Stick card in a MS-to-SD adaptor, but I 
proved that this worked by successfully putting it into another PC's SD 
reader. If I'd had a spare SD card, I'd have tried that, but I didn't have 
one.