Problem:
I used Active@ Partition Recovery to detect and recover a deleted partition successfully. However after reboot FDISK is not able to see the partition. Also if I try to access the C: drive, an error message is displayed saying that drive is not valid.
Reason:
Both Partition and Master Boot Record were damaged.
Solution:
Re-create MBR by running FDISK with parameter /MBR:
A:\>FDISK.EXE /MBR
After MBR is re-created, partitions can be detected if Active@ Partition Recovery restored them successfully.