wonder where you got you copy of vista from (cough) A failed installation or indeed activation of vista changes stuff in your bios or, more accurately, how windows interacts with your bios, sending you in this loop...
Anyway, you have to do a reformat and reinstall from an xp disk... to do this:
1. Restart your computer and enter the bios setup. If you dont know how to do this, start your computer and watch carefully for instructions. It should say something like press (x) to enter setup or to enter bios, where (x) is the key you need to press to enter. For example...my key is the F2 key and when my computer starts I tap continuously on it till I enter the bios.
2. Having entered the bios, navigate till you have found the boot sequence options. This is slightly different in every bios but basically it puts in order the devices your computer boots from 1st 2nd etc. You need to choose your cd rom device as 1st boot option. Save and exit the bios and restart the computer with your xp disk in the drive.
3. Reformat your drive (you'll lose all the info on it) and reinstall windows xp.
If you arent sure how to format the drive post here again and I can give you instructions. If you dont want to lose the information on the drive (and have an extra drive where you can install windows) let me know and I can give you instructions on how to do it.
