HOw to UNinstall a ubuntu on a dual boot system?

[mahela007]

I have installed ubuntu after windows so that the PC is not dual boot. However, I want to uninstall ubuntu and I don't have the windows disk. What can I do? (This is just a hypothetical question.. I'm just wondering if this is possible.)

[oldfred]

If it is older windows XP or older supergrub, testdisk (in repositories), and most repair CD's have ways to recover the MBR for windows as it was the same for all old windows.
http://www.supergrubdisk.org/

Vista & Win7 are different:

How to restore the Ubuntu/XP/Vista/7 bootloader (Updated for Ubuntu 9.10)
http://ubuntuforums.org/showthread.php?t=1014708

If your PC did not come with a complete Vista or Win7 installation CD, you can download a Recovery Disc at the following links:
Windows Vista Recovery Disc
http://neosmart.net/blog/2008/windows-vista-recovery-disc-download/
http://neosmart.net/blog/2009/windows-7-system-repair-discs/
Vista will not repair XP(they create the boot sectors differently)
http://neosmart.net/blog/2009/windows-7-system-repair-discs/

How to restore the Windows Vista bootloader
http://support.microsoft.com/kb/927392