Homebuilt PC not reading HDD's

Hey all, for some reasons my HDD's will not POST in the bios or anywhere for that matter. I have tried running the raid controller in RAID and AHCI, but, neither works.

Here is what I have inside.

- MSI Diamond P45 Motherboard
- Intel Core 2 Quad Q9550 Processor (Frequency 2.83GHz, FSB: 1333Hz, Transistor: 45nm)
- XFX 260 GTX graphics card (1)
- 4gb of Corsair DDR3 Dual Channel Ram (4096MB PC10600 DDR3)
- BFG 800 watt PSU
- Seagate SATA ATA 7200 RPM 500GB Harddrive (1) (Main HDD - Has Windows XP 32 bit OS)
- Western Digital 5400 RPM 2TB Harddrive (1) (This is run as an external)

My computer WAS running fine, and one day it just stopped booting and now it would even read the HDD's.

Normal System temperature at idle is 35 degrees and about 40-45 degrees with multiple applications running.

You say your HDDs won't POST, does that mean the computer hangs during POST, or do you get to the "Invalid System Disk Error" message after the BIOS has fully POSTed and tries to boot your system?

Have you tried booting from the CD/DVD drive (i.e. use a Windows or Linux boot CD)?

Have you moved your internal drive to a different SATA port? Have you tried using a different SATA cable and power cable (those power cables tend to have fragile connectors on them)?

Does your motherboard have a "Legacy Parallel ATA" setting, and does that solve anything?

Have you tried the HDDs in another system? Have you tried installing a different HDD in your system?

When you say HDDs plural, are you also talking about your external drive too? Is it eSATA or USB (I'm guessing eSATA)?

If both drives are SATA/eSATA and neither are showing up, I'm guess your SATA/RAID controller or chipset is bad. If you can see the drives on another computer, then its probably your computer. If you install a different HDD in your machine and it doesn't see it, then its definitely your computer.

If you've done all the moving and swapping and nothing works, might be time for a new motherboard. Of course, maybe you could use an add-on SATA/RAID card, but I wouldn't continue using a damaged motherboard, something else is bound to fail for whatever reason your SATA/chipset failed.