NTLDR is missing...

I know this is a common problem and I've been doing my best to use previous forums, but there's an issue for my specific situation. I made a few mistakes along the way...

I have a Gigabyte GA-EP43-DS3L motherboard.

I have an ATI x1550 media graphics card in my computer, but I got a hold of a Radeon 4650. I wiped my computer of the x1550 driver, then plugged in my 4650 and went to start my computer, but there was just a loud beep and nothing showed on the screen. It was at this point I realized my power unit didn't have enough wattage to handle the new video card. I restarted a few times, but still the loud beep. So I plugged my x1550 back into my computer and the startup kept going through a cycle. Eventually I got fed up and decided to reinstall the OS.

My computer was using Windows XP Pro, but when I went to install I put in Windows XP Pro 64-bit by mistake. I don't know if that matters, but I wanted to mention it. I booted off the XP 64-bit CD, reformatted the drive, got about halfway though the installation and it froze. I restarted and got the NTLDR error. I put in a regular XP Pro CD, but same error. It says "Boot from CD/DVD>Press Any Key to continue." I press enter or "Y" and still get "NTLDR is missing>Press Ctrl+Alt+Del to restart."

I went to go into bios, but it had a password (and the kid I bought the computer from forgot the password), so I took the battery off the board and jumped the CMOS. When I restarted I got into the CMOS, set the CD/DVD as the first boot device and the HDD as the second, but I'm still getting the NTLDR error.

I have 4gb of DDR2 RAM, so I unplugged them and used them one at a time, but I still get the same error. Nothing is burned or bubbling on the board (however, I've read this board is supposed to be resistant to that).

I'm not extremely good with computers, so I'm at a loss at this point. This is the first time I've broken down to post here Cheers.