OEM hard drives do not come with cables. Your power supply will have the SATA power cables, just make sure you have enough. They are usually black and thin and if you look at them they have a bunch of little "pins" in them. The other connector for drives is called molex which connect to older drives. These have four large pins that you can easily see. Your motherboard probably came with some SATA drive connectors. If these reach use those to connect your motherboard to your hard drive and CD/DVD drive. If you need cables, just buy any SATA II cables that are long enough to reach your drives. If you do not have enough SATA power cables buy a splitter that will take one connector and make it 2 or 3 or 4. Good luck.