I presume you have installed Ubuntu 10.04 or 10.10. If you want to change the boot order in you have to edit the grub file.I am copy and pasting the extract from a website.I hope it will help you.
The file to be edited is now “grub” located in /etc/default/ folder, you can edit it by running the following command from terminal (sudo gedit /etc/default/grub). The contents would look like this:
If you change this file, run ‘update-grub’ afterwards to update
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
# Uncomment to disable graphical terminal (grub-pc only)
# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo’
# Uncomment if you don’t want GRUB to pass “root=UUID=xxx” parameter to Linux
# Uncomment to disable generation of recovery mode menu entrys
To change the default boot option, you just need to change the GRUB_DEFAULT parameter. 0 is the first entry, so if you want windows to be your default boot option which is, say at, 2nd position in the grub menu, then you just need to change the GRUB_DEFAULT value to 1 and save the file and close it.
After that type the command below:
The are good documents in help.ubuntu.com website on grub2.