im trying to do the same thing as you are my guess is to just pull out the PSU and parts leave the Screen Psu alone take the microphone speakers everything nand look for the parts to run when i get my cube parts ill reply and show you what i mean
AMD Athlon 64 3000+ @ 1.9ghz, RaidMax X-1, 520W RaidMax PSU, 1GB A-Data DDR400 Ram, DL-16x LG DVD Writer, Gigabyte GA-K8N-SLI, 200GB Sata, 2x 20GB PATA 1x 40 PATA, Nvidia 6600 256mb