Use something like VMWare or VirtualPC. Carrara will only see one processor, but you can suspend the virtual machine at will and save it to disk. After that you just shut down your host OS. Power comes on, you boot up, start VMWare and it will pick up where you left off. For something like rendering, VMWare will actually run pretty fast, my test showed it at nearly 100% native speed when just rendering. Good luck, Eric Winemiller Digital Carvers Guild 3D plug-ins for Carrara http://digitalcarversguild.com

Eric Winemiller
Digital Carvers Guild
Carrara and LightWave plug-ins