This page is for setting up a menu (bootloader) that comes up when you first turn on the Aspire One (for choosing the Operating System to load.) It assumes you have already installed XP, Vista, OSX, and/or Linux on separate partitions.
If one of your Operating Systems is Vista, you'll want to use this bootloader. If Vista wasn't the last OS you installed, you need to use the Vista MBR recovery to make sure your computer is using the Vista bootloader.
Then boot Vista and run this program to add OSX, Linux, and XP to your boot menu: EasyBCD
The XP bootloader (boot.ini) generally is only able to load XP or 98.
The grubldr bootloader can also be started from the XP bootloader and then used to boot OSes that the XP bootloader cannot if you wish to leave your MBR intact it is available from the Grub4DOS project
This is the linux bootloader. EasyBCD uses it within the Vista bootloader to add linux to the menu. You can also use it by itself, but I have no idea how...