Can I overwrite vista with XP dual boot with ubuntu ?
Not easy this one Im afraid! The reason being is that Windows has a habit of installing its own bootloader. I am assuming you currently use GRUB as your bootloader? In theory, its perfectly plausible to move anything you want to keep to a USB stick or another partition, delete the Vista partition, install XP on that deleted partition and then reinstall GRUB and configure it so that it detects Windows XP and Ubuntu (there are threads on how to do this in the Ubuntu forums www.ubuntu.com). So it IS do-able. I personally wouldnt do it that way however. The easiest way by far is to simply back anything up that you want to keep onto a USB stick (or even a web based storage facility such as Adrive – www.adrive.com), install XP from scratch (deleting all the partitions and formatting the drive at the same time) at which point you can then instal Ubuntu and use its partition manager to set up your dual boot. You can then split the drive easily and Ubuntu will set that up for you and configure
