MiniMRP
MiniMRP for Windows 10, 8, 7, Vista and XP(SP3) is a low cost, easy to use Inventory and Parts List Manager with Multi Level BOM (Bill of Materials) and other MRP-Like features usually only found in larger ERP/MRP packages.
If you are looking for an Inventory Manager with Multi Level BOM capability without the associated running costs of an overweight ERP/MRP system then you really should take a closer look at MiniMRP.