Computer disk hardware configuration problem (Windows 7 boot)

Hi all,

Here's what's happened...

i have Windows 7 on a 500GB SATA hd running fine.

Yesterday I decided to install Windows XP Pro SP3 on a spare 160GB SATA HDD which I have, and I did this via the notebook upgrade bay (2nd HDD caddy) where the DVD drive would be. I left my 500GB internal (Windows 7) HDD in the computer and during the XP setup DVD specified for it to install on the 160GB HDD.

The problem is every time I boot my computer, it tries to boot XP.. even if i change the boot sequence or try to manually boot the internal HDD from the boot menu...

i tried to remove the 160GB XP hard drive hoping that this would leave the computer to boot the 500GB Windows 7 x64 OS... But instead i get this message on the screen..

"Windows could not start because of a computer disk hardware configuration problem.
Could not read from the selected boot disk. Check boot path and disk hardware.
Please check the documentation about hardware disk configuration and your hardware reference manuals for additional information."

Can anyone give me any advice on what I need to do to be able to boot properly into my Windows 7 HDD again?

I have Hirens BootCD at my disposal and have managed to boot into Windows 7 fine using the option presented on the first screen. After a reboot the message above returns...

Many thanks in advance,

UPDATE: I have also tried to run a startup repair from more than one Windows 7 installation DVDs and get the message: "This version of System Recovery Options is not compatible with the version of Windows you are trying to repair".

Unplug the XP drive, boot into the Win7 disk for your licensed version Win7 Professional x64 English Official ISO Download burned to disk or flash stick using Windows 7 USB-DVD Download Tool

Mark Win7 or it's 100mb System Reserved (if you have it) Partition Active,

then run Startup Repair - Run 3 Separate Times until Win7 starts and holds the System Active flags.

Then plug back in the XP drive, making sure Win7 remains first HD to boot in BIOS, set either under storage devices as Primary HD or first in BIOS boot order. Trigger XP drive using BIOS Boot menu key if needed, or if you don't like that then install EasyBCD to Win7 to add XP to a Windows Boot Menu on the Add OS Entry tab.