xp should be in a separate partition on your pc.
go to the System Configuration utility (Start + R ---> msconfig) delete the old OS, and set Win 7 as the default.
use windows disk management (type 'disk management' into the start menu) to delete the xp partition.
alright well, when im starting up it comes up with windows boot manager and asks me to select windows 7 or windows xp professional setup if i select xp then there comes up a message saying it could not be started because a file is missing, i can get the name of the exact file if that helps?
Once downloaded install the application and launch it.
Look at the sentence at the top of the opening screen, if it says something like "There are two entries in the Windows bootloader" click on the "Add/Remove entries" button on the left. Highlight Xp in the existing entries on the right then click on the "Delete" button right above that has become red.
Click the Save button then exit out of the application and reboot.
Hopefully now your dual boot option doesn't exist anymore. You can uninstall easyBCD if you have no need for it anymore.
You need to look at the rebuild /bcd command down the page a little.
If the default operating system which boots once the timeout has lapsed is Win 7 you can also adjust the timeout option so the boot menu doesn't appear, it's a bit of a cheat but a workaround nonetheless.
The command to change the timeout value is:
bcdedit /timeout (your value in seconds) bcd<space> /timeout<space> (your value in seconds)
The default is 30 seconds so if you want to change this to 1 second you would put in:
bcdedit /timeout 1
This means the boot menu will appear for 1 second, I'm not sure if you can set this to 0 though. Be sure that Win 7 is the default boot OS.
You can also edit the timeout option in msconfig under the boot tab.