CCT is essentially correct, with an exception or two. Double check all those SATA cables and socket locations. There is the potential for problems. I don't have a P5B board map in front of me right now, but I know there are four P5B motherboard versions: P5B, P5B-E, P5B Deluxe and P5B Deluxe/WiFi-AP.
The P5B is the ASUS basic P5B model... can we assume that is what you have?... No... looking back, I see that you have the Deluxe.
P5B-E uses ICH8R south bridge instead of ICH8 like on P5B, so on this board there are six SATA-300 ports controlled by the chipset supporting RAID (0, 1, 10 and 5) plus two extra ports controlled by a JMicron chip. P5B-E has also two Firewire ports. The rest of the specs are equal to P5B. P5B Deluxe has two Gigabit Ethernet ports, two x16 PCI Express slots (the second one running at x4), only one x1 PCI Express slot and a passive cooling solution using a heat-pipe. The rest of the specs are the same as P5B-E.
ASUS P5B has four DDR2-DIMM memory sockets, supporting up to 8 GB officially up to DDR2-800, however this motherboard supports DDR2-1066/PC2-8500 memories. On this motherboard sockets 1 and 3 are yellow and sockets 2 and 4 are black. Configuring DDR2 dual channel on this motherboard is pretty easy: just install each module on a socket with the same color.
On the hard drive storage side, where your interest lies, there are a total of six SATA-300 ports, four provided by the south bridge (ICH8) and two provided by a JMicron JMB363 chip. The ports controlled by the chipset do not support RAID, as the south bridge used is ICH8 and not ICH8R, however the two ports controlled by the JMicron chip support RAID0, RAID1 and JBOD. One of these two ports is located externally, for connecting an external drive. This port is different, as it is a port multiplier connector, SO YOU CANNOT USE A REGULAR SATA CABLE ON IT.
Port multiplier technology is targeted at external hard disk drives, allowing you to connect up to 15 Serial ATA hard disk drives to a single SATA-300 port. In order to use more than one SATA HDDs on this port you need an external port multiplier bridge, which is an external device sold separately. The hard disks are connected to this device, while this device is connected to this port multiplier port, which, in turn, is internally connected to one of the SATA ports controlled by the JMicron JMB363 chip on the motherboard.
It is critical to observe that the single ATA/133 port available on this motherboard is controlled by the JMicron chip, not by the chipset. This means that if you still have a parallel IDE optical drive it will only be recognized on Windows after you install JMicron’s driver. The problem is that this driver comes on the motherboard CD-ROM, and you won’t be able to install it, as the system does not recognize your optical drive. You can download the driver from the net, however the driver for the on-board LAN port is also on the CD-ROM… The only option you have is to copy the JMicron driver from the CD to a floppy disk or a USB flash drive using another PC. This problem happens not only with this motherboard from ASUS, but also with all other motherboards based on Intel P965 chipset. If you have a SATA optical drive you probably will not face this issue.
You might want to think your problem through in relation to the above, and retrace all your steps to assure you haven't missed something too simple to look at.
Again, I do not think your problem is a motherboard issue... meaning a failure or a defect, but this info here should clear up some flow problems.