Dell Precision 650 - Manual (Page 110)

Serial ATA Drive
8. Check all connectors to be certain that they are properly cabled and firmly seated.
9. Close the computer cover.
10. Connect your computer and devices to electrical outlets, and turn them on.
1 power cable
2 hard-drive cable
1 power cable
2 serial ATA hard-drive cable
NOTICE: To connect a network cable, first plug the cable into the network wall jack and then plug it into the computer.