I've been running Vista and XP side by side for a few months now, and what I designated as a small partition has slowly got bigger and bigger until there was no space left on my Vista partition, so today I decided to re-jig my partitions. No problem, but due to the lack of partition managers for Vista, I had to boot back to XP and fire up Partition Magic. The problem started when I tried to boot back to Vista, which gave me loads of errors about files not being found before refusing to boot. I was pretty baffled by this point, because from XP I could see that the files that Vista was complaining were missing were right there where they were supposed to be. To fix Vista, I had to boot from the install CD and use the automated recovery tool, but then when I started Vista, my drive letters were all wrong. Now I could see which partitions matched which drive letters, but windows wouldn’t let me change them because they were for the system drive. After a good two hours of trawling through technet, I eventually found a solution:
1. Go to the following registry key:
2. Find the drive letter you want to change to (new). Look for "\DosDevices\C:".
3. Rename it to an unused drive letter "\DosDevices\Z:".
This frees up drive letter C.
4. Find the drive letter you want changed. Look for "\DosDevices\D:".
5. Rename it to the appropriate (new) drive letter "\DosDevices\C:".
6. Click the value for \DosDevices\Z:, click Rename, and then name it back to "\DosDevices\D:".