Dual boot system
 

I want to set up a dual boot system with Linux Ubuntu and Windows XP. How can I do this and do I need a Windows install disk because i only have a restore disk?

No, although you may wish you had one if things go awry... :) The gist goes like this:

Backup important data
Partition your drive (I use qtparted from Knoppix live cd -- nice gui, works like partition magic, good on NTFS)
Reboot -- insert Ubuntu disc
Install Ubuntu, put grub in Master Boot Record
Reboot

Tada.

If all you have is a restore disk, two hard drives one set to master other to slave with jumpers is your only choice unless you can change the partioning scheme on the restore disk somehow. Restore disks usually take up the complete space of the hdd they came with. Maybe you could upgrade the size of the hdd and if there is unused space left after the XP install, then you would be in business.

Try Partition Magic to resize your HD partition create a swap partition and a linux partition. Install your Linux OS after it was finish automatically you'll have a Dual boot system.

With Windows already installed...

Backup
Create empty space on the HD
Install Linux and put the bootloader on a floppy. This leaves Windows untouched.
When Windows eventually fails, reconfigure the maching Linux-only......;)

Seriously, I am confused by all the folks that do not have Windows install disks--does this mean there is no way to re-install in the event of HW failure or other catastrophe??