I try to boot from the Windows XP disc and it wont let me, it says there is no Harddrive, when i do have a hard drive. I just want to uninstall ubuntu and get windows.
Whilst installing Ubuntu the hard disk was formatted as Ext4, and windows does not recognise Ext4 or your hard disk.
You need to format the disk using a file system that windows recognises such as NTFS or FAT.
The simplest solution is to boot your computer using the Ubuntu live install disc,
Once that is done windows will recognise the disc and allow you to install windows XP.