how can I uninstall ubuntu from a vista-unbuntu dual system

If grub was installed on the MBR of you Vista drive you will need to restore your Windows MBR in order to boot directly into Vista. You will have to boot from the Vista CD and repair from the command line

bootrec /fixmbr

Also Vista will not be able to use the ext3 linux partitions that Ubuntu was on. You can use Vista disk management tool to reformat the linux partitions to NTFS.

Hope this helps

Have you installed Ubuntu inside Windows ... ?

I suggest you to install Ubuntu NOT using Wubi.

If you have installed Ubuntu via Wubi please uninstall it read http://wubi-installer.org/faq.php

Installing Ubuntu using Wubi make Ubuntu less robust and all problems that you will have to Windows can be affect your Ubuntu partition file.

I strongly suggest you to install Ubuntu+Windows in dual mode creating a real Ubuntu ext3 partition.
In this mode you can use Ubuntu and Windows ad usual and then using installed Ubuntu you can save or repair damaged (due viruses or other issue) Windows partitions data.

- Here the steps to install Ubuntu 8.04.1 https://help.ubuntu.com/community/GraphicalInstall (pretty the same for Ubuntu 8.10)

Is very easy to install, if you need info please ask.

Thank you

Truong Nguyen,

if you want to getr to the situation that you still have Ubuntu-8.10 and Vista, but Ubuntu-8.04 is removed,...
then you can do this thus:

In Ubuntu-8.10 edit the file /boot/grub/menu.lst
remove the items referring to Ubuntu-8.04 (every item is e few lines), and save the file.

Now grub let you choose between Ubuntu-8.10 and Vista...

The Disk-space given to Ubuntu-8.04
can now be used for either Ubuntu-8.10 or Vista,
or you can leave it there and re-use it when Ubuntu-09.x is coming.