If yor friend was smart, he backed up the registry before fooling with it. If so, try re-merging the backup into the registry and reboot.
But since people rarely backup anything, I'm going to assume that no backup exists and work from there.
If you're using Windows XP, try using System Restore to revert to a time before the problem began.http://www.microsoft.com/windowsxp/using/h...temrestore.mspx
If that doesn't work, we can try to reactivate the logical disk from the Disk Management snapin.
Click on the Start
button and slick Run...
in the start menu.
in the Run... box and press <Enter>
From the left hand tree, click Disk Management
. Wait for the snap in to startup.
Where we go from here depends on what the Disk Management console says. If you could post a screenshot
, that would be helpful.
Post back soon!