Before you format xp you will need to go onto Linux and create a grub boot disk by typing grub-install /dev/fd0. This will create a floppy disk which you can use to start Linux after you have removed and reinstalled xp. After removing and reinstalling xp use the disk to get back onto Linux and use grub-install /dev/hda to restore the Linux boot screen.
Yes.
If your restore requires a windows disk then you cannot restore without one. Most do not require a windows CD. Most include the windows files in the manufacturer restore.
Yes, if you have copied all installion files on your hard disk. If you haven't you cannot reinstall Vista.
The only possible way to do that would be to purchase a Vista disc and run from that.
If you don't mind losing all of your files then yes, it is ok.
You can make it the default option in the bootloader. Or you could reinstall the Windows bootloader, but it will not allow you to boot Linux without modification.
Yes. Reinstall Windows XP.
You cannot do this unless the manufacturer has specifically provided a way for you to do so, in which case you should follow the manufacturer's instructions.
Data safety in the event of winders screwing up. If you have all your photos etc on a partition with windows installed on another, you can reinstall windows in the event of a serious error without losing your files.
Listen, without interrupting ... then calmly discuss the matter or situation.
Use the following commands in Windows XP: Start, Run, type sfc /scannow This will restore all Windows files and drivers back to their original condition, without losing or erasing information.
Without making major changes, you need an AV to remove a virus. There are several free ones like Avast!. If you really need to avoid an AV you can reinstall windows or install Linux.