Can you explain exactly how did you install. You should not need the DISK in drive to boot at all.
EasyBCD is easy enough to use, I prefer --> orb --> type msconfig -->
move to boot... should see this: or very similar:
I burned the ISO to a DVD, then rebooted my PC and set it to boot to disk then used custom install to select the empty partition (100gb) install went without a hitch and the computer restarted. when it came to the 'press any button to boot for CD/DVD' i pressed nothing and windows 7 booted, i downloaded drivers etc which required a restart, this time i took the installation disk out of the drive, so the 'press and key to boot from CD/DVD......' part did not come up then the computer just booted straight into XP with no option to do other wise.
So i restarted again and put the disk back in the drive. the 'press and key to boot from CD/DVD......' message came up, i pressed nothing and it booted straight to windows 7.
so i did a little digging and found the /bcdedit tutorial and set up the XP part as per its instructions.
Restarted, took the disk out, straight to XP, restarted again, left the disk in, press any key message, let it time out, got a boot menu.
from this windows 7 booted fine, so i restarted to see if i could boot to xp from this menu, but it just restarted my computer when i selected it.
So i downloaded easy BCD to see if that would help, but no difference.
also tried repair install with no luck.
I have since formatted the partition, disconnected my second unused HDD and tried to reinstall, but now i get 80070017 errors, so i tried to burn a new disk and i think my DVD drive may be broken as i cannot even boot to this disk without getting I/O device errors