You deleted the wrong partition with Partition Magic or FDISK, or you deleted a volume after realizing you had used the wrong partition.  
 
Possible causes:  
· You simply lost track of your partitions, or didn't read this document through before starting ;-)  
 
What to do:  

• A deleted partition isn't necessarily the end of things. All the data is still there, it's just that the operating system doesn't know the start and end of it, so to speak. All you have to do is to recreate the partition, EXACTLY as big as it was and in EXACTLY the same place on the disk. If the partition occupied the whole disk or was between two other partitions, this shouldn't be a problem as long as you use the same program to recreate it as you did to delete it (rebooting in the meantime doesn't do any harm, but doesn't help either).  

• Now the important thing, especially if you use Partition Magic, is that you DO NOT CREATE A FILESYSTEM ON THE NEW PARTITION! The thing is, if you create a partition with Partition Magic and tell it to use a particular filesystem on it, that is basically the same as formatting the partition. It overwrites the areas of the disk where the filesystem was with a new, empty filesystem. If this happens, there is NO WAY to recover your data (unless you go to a professional company, which will cost you $$$$$). So: Select "Unformatted" when Partition Magic asks what filesystem to put on the new partition! After creating the partition again, use LVM to create a volume using it, and it should be fine. In case you don't see any files on the partition, run CHKDSK; this will look for filesystem structures and restore the files on your disk