Trouble with SATA Hd

I have a AMD Athlon 64 3200+ with 1 GBit of RAM. The Motherboard is MSI VIA K8T800.

My motherboard has room for 4 SATA drives to be installed. I had an 80 and a 120 Gbit HDs installed. I was having problems with the 80 Gbit showing correctly. Sometimes when I reboot computer, it shows the drive as a cd-rom drive and not a hard drive.

I then added a 300 Gbit SATA HD to the computer on the 3rd slot. When I did this, the problem went away and all 3 drives showed up correctly ever since.

Well today I found another 500 Gbit on sale at Best Buy, so I threw it in the computer when I got home. The new drive does not even show up in the drive manager, or when I run the software that came with the new drive. And also the 300 Gbit hard drive is now showing up as a cd-rom.

I have removed the new 500 Gbit HD and the 300 is still showing up as a cd-rom.

Please let me know if you have any thoughts or have heard of this problem before.



Thanks for any info you can provide.