I have xubuntu in a computer at the moment, but I want to put Windows 7 on it. So when I try to boot either Windows 7 or Windows XP, I get this error.
What is going on? Why do I get Ubuntu error when trying to put up Windows?
From where or what do are you trying to boot windows 7 or xp?? If you want to choose between windows 7 or xp and Ubuntu on start up you will need to install windows first and then Linux on another partition to get a proper grub file. If you reinstall Ubuntu after installing Windows you can choose that you want to install Ubuntu alongside Windows and you should be thine.