I have two problems.
1. trying to install a brand new SATA II Western Digital 400 GB hard drive. Windows reports that the drive is full when it is only something like half full. I later placed the jumper to make it 150 speed. That didn't change anything. I was wondering if the problem was the motherboard, so I decided to flash the bios from version 1014 (asus p4c800-e deluxe)to the latest 1021 I believe it is. It successfully flashed, but now says "overclocking error", f1 enter setup, f2 default settings. F2 goes into windows fine. Here is problem 2:

2. Upon saving changes in bios setup, monitor shuts off (I lose my video signal) and that's it. It fails to update the changes. Was wondering if it was the battery, but clock seems to be fine.

Can you help?

Obviously, you need to get your machine working first! You will always get better motherboard support from the manfacturer's own forums. So go here, register and post if necessary:

http://member.asus.com/login.aspx

As to adding your SATA drive....It can't have been "brand new", if you admit it was half full. For XP or Vista, as I guess you know you need to go to "ComputerManagemet" and "Disc Management" first to add the disc.

You didn't say if this computer is XP or Vista. I found with my most recent eSATA disc, If I formatted on XP and added things, Vista would not see it and wanted to format. My XP was a desktop with an internal SATA card (all other ports were inuse) and the Vista machine was a notebook with an eSATA "ExpressCard". Since I had only put a few things on and thus were copies, I finally let Vista do the format, and XP was fine with it. I don't know why the other way around did not work, I'm just glad I found it before it was an emergency!

Also, be sure to properly describe the filesystem type. If you formatted it NTFS and took it to another machine and said, say, FAT32, it might report it "full" as you described.

still trying to find a solution. Asus and WD still haven't emailed back.

I've also discovered my portable usb external hard drive is doing the same thing: Windows thinks it's full.

SATA drive was brand new. I filled it half way before I discovered problem. I formatted by NTFS and I have Win XP Pro.