Ok I did somthing weird and have no clue what i did wrong i'm using Ubuntu Wubi version 9.04 and I need to know is there any way I can get ubuntu back to default settings through the terminal or by so other means. So that I don't have to reinstall ubuntu.....

Thanks so much, Ian ;D

I don't understand what you mean by "Desktop D:". Please indicate what problems you are having and what you changed before the problems.
Given a time frame to work with, you could check files in ~/.gnome2 and ~/.config to determine which files were altered.
e.g.
find ~/.gnome2 ~/.config -ctime -3

If it's just desktop settings and program settings the easiest way to do that is this in /home/<user> or 'cd ~/':

rm .* -R

If you have Wine installed and any programs inside I would severly suggest you rename the wine directory.... such as:

mv .wine wine -R

That might be correct? That will force all the desktop settings to the default.

You could also just do it folder by folder, I'd start with removing .config and any folder that is named like your WM, such as if you use gnome get rid of .folder with gnome in it. This is a very ugly way of doing it I know, but it's very easy to understand and shouldn't remove anything that you need.

Deleting all hidden directories in the $HOME directory is a bit of overkill, and almost as drastic as reinstalling. Renaming ~/.gnome2 and ~/.config would be less drastic.

Some other things to look for are files owned by root. If you run a gui program as root, it could have altered a config file or log file, making it unreadable. These could be located in /tmp/ as well. If there was a runaway application that caused the .xsession-errors file to grow in size, filling available disk space, that can prevent logging in to Gnome or KDE.

After making some changes, such as hostname, you need to log out and log in again. Some other changes such as to group membership or the sudoers configuration can require a restart. Orphaned pid files in /var/run can prevent programs from starting. A kernel upgrade requires a restart.
Removing all files from /tmp/ often can help.

how about sudo apt-get remove ubuntu-desktop and reinstalling it again.

you would have to do purge, but then that might not remove the user's files just the config files for the system. jschiwal is right though, .gnome2 and .config could just be renamed.