I added a new drive but it did not appear in Win 7 - even though it was there in the bios. Used a partition manager to find and re-activate it.
Had problems with a failed load from a disk image on a laptop - partition had vanished! Again, ran a partition manager which showed the partition was there but marked as inactive. Made it active and no problems.
Gave my son a s/h disk from ebay which would not show up, even though he could hear it running and it was visible in the bios. He downloaded a partition manager which immediately spotted the problem and fired up the disk without any intervention or input from him; worked fine after that.
So don't be so quick to dismiss the use of a partition manager.