How to "re-attach Parts" into an assembly

Ok so PDM has been giving me some interesting problems.

I accidentally upped the revision on a few parts/drawings, so i was doing a good few "roll backs"

now Roll back is on the same tab as Delete which as i have found out is REALLY dangerous!!

Now while doing this mass "roll back" i accidentally Deleted a part.

the part went from the Tree. and the Drawing Dropped to be at the same level in PDM as the top level.

I then opened the Assembly the part belongs to. It opens fine. even tho there is a part "missing" from the assembly, The only thing i can guess is that it retrieves it from another assembly in the vault (when really it shouldn't).

Ok so tried to check the assembly back in and it went in, it said it was checking in Said deleted part as a New part.

However in the tree it was the same. No part in structure and the drawing out of the structure.

Next i deleted the Drawing and repeated the open and check in.

This time it placed the Part and Drawing Outside of the Assembly.

So 3 questions

1)When the part is deleted from the Tree in PDM where is it getting it from and why?

2)What was going on with the check in

3)How to i Re insert this part and drawing which is now outside the tree in PDM back in?

SolidworksWorkgroup Pdm