Slowest part of a computer system is HDDs. They have max. 300MB/s against GBs of bandwith of CPUs, graphic cards. CATIA will work for your computer but you may need change it soon. "Middle range" computer parts for "enterance level" CAD. Graphic card's gpu is more important than it's memory...
Did you try Toolbox? It's at right of the Solidworks screen.
If it's not visible, you can add it by following Tools-->Add-Ins from the menu.
Once Toolbox placed at right, you can simply create parts by right clicking and selecting "create part" option.
You don't need a bounding box.
1. set up pulling direction.
2. Transfer surfaces marked as other to core-cavity
3. Make parting surfaces with surface tools
4. Make mold using mold tooling workbench