XP won't dual boot to Windows 7

I have Windows XP installed on C.
-I partitioned C into halves, the new partition was renamed S and its a logical ntfs.
-I then installed Windows 7 32bit onto the S partition.

Problem: The boot screen never comes up when I start my computer; its automatically goes to XP. However, if I have my windows 7 dvd inside, and I don't press a key to boot from CD/DVD, it will go straight to Windows 7.

I tried running EasyBCD on both XP and 7. XP doesn't recognize that I have another OS so EasyBCD is just greyed out (It says "The boot configuration data store could not be opened. Would you like to manually load a BCD registry?"). Windows 7 acknowledges itself in EasyBCD but can't find XP.

-To get EasyBCD in 7 to find XP I added it myself
-It worked, boot screen showed up
-But as soon as I take the 7 dvd out of the drive everything reverts back to normal

Please Help!

You'll need to recover the System Active boot files into Win7 to start it up and then add XP.

First mark Win7 partition Active: Partition - Mark as Active

Now boot the Win7 DVD Repair console, accept any offered Repair. When it won't start, boot back in, click through to Recovery Tools list to run Startup Repair up to 3 separate times with reboots until Win7 starts:
Startup Repair - Run 3 Separate Times

When Win7 starts install EasyBCD 2.0, add XP, accept offered boot files, Save, Restart.

If this fail, I would use free Partition Wizard bootable CD to rightclick>Wipe the Win7 partition before trying install again. Residual bad code may have caused the installer to not configure the Dual Boot as it is supposed to do.

It is much easier BTW to use XP virtual mode within Win7, or Dual Boot on separate HD's booted via the BIOS Boot Order and Boot Menu and not Windows. http://www.vmware.com/products/player/

Coincidentally, my harddrive is dying so I have to replace it. I will do a fresh install of both OSs and if I still have the same boot problem I will try this.

Thanks for the feedback