Thanks once again Jon and good spot with the SW Coast path.
I used this link to change the drive letter so they were the same:
http://windows.microsoft.com/en-gb/windows/change-add-remove-drive-letter#1TC=windows-7
It seems as though every time I plug my HDD drive in it seems to populate a LR Catalog in my Pictures Folder. I understand that this is the default location for LR to store the catalog but not what I want to happen as I want to use the HDD all the time so I can use the 2 computers. I think we are there now and thank you once again for your help.