I am running Mechanical 2004 DX, so your locations might be different.
Title Blocks:
C:\Program Files\Autodesk\MDT 2004 DX\ACAD\Gen\DWG\Title
Borders:
C:\Program Files\Autodesk\MDT 2004 DX\ACAD\Gen\DWG\Format
The "Mechanical Help" is very good on this subject. Use this search term: title block, customize
Inventor 2013 64-bit
Dell Precision 690
» CPU: Intel Xeon 5160 @ 3 GHz
» RAM: 8.00 GB
» Video: nVidia Quadro FX 3450