I will advise you to do everything said by "Andrew E." through Windows
itself and I am not totally agree with Andrew suggestions. Deleting and
recreating partitions through Recovery Console without Backuping data first
is not a good idea and what if you want to remove the windows which is
installed on drive C. If you delete the C partition using diskpart command
then you will not be able to log on to newly installed windows as well.
1. First Log on to the Windows that you want preserve.
2. Note down the partition for each installed Windows. Your mind should
clear about it and you should know that on what partition each Window is
installed.
3. For instance, you or log on to Windows that you want to preserve is
installed on C drive and the Windows you want to remove is installed on D
drive. Then the easy method will be copying all of your data to another
partition (like E drive) and then Format that particular partition. Later,
you can remove the entry from Startup menu too.
4. But in another case, if your newly installed Windows is on D drive and
you want to remove the Windows of C drive then you should be careful about.
In any case, you should backup your data first on a removable device or
another drive which doesn't consist any Windows file like E Drive. If
something goes wrong with either Windows then you will safe at all. Windows
will not let you format your C drive as it is System Partition of your D
drive's Windows as well. So what you have to do is, copy all your data to
another drive and remove the folders manually. You must take care of
Documents and Settings folder.
THIS MOSTLY HAPPENED WITH MANY USERS WHEN THEY REINSTALL WINDOWS. FOR FUTURE
REFERENCE, I WILL ADVISE YOU THAT IF YOU WANT TO REINSTALL WINDOWS THEN YOU
FIRST BACKUP YOUR DATA TO ANOTHER DRIVE OR REMOVABLE MEDIA. BOOT FROM
WINDOWS XP CD AND REINSTALL THE WINDOWS ON THE SAME PARTITION WHERE IT WAS
ALREADY BEING INSTALLED AND THEN TELL THE SETUP TO FORMAT THAT DRIVE. THAT
WAY IT WILL REMOVE THE PREVIOUS WINDOWS AND WILL INSTALL A FRESH COPY OF
WINDOWS ON SAME DRIVE.
5. To remove the unwanted entry from Startup menu or to disable the Startup
menu:
Right-click on My Computer and choose Properties
Click Advanced tab
Click Settings button under Startup and Recovery
By default the Windows that you are currently log in to will be selected in
Default Operating System. If that is the Windows in whcih you want to always
log on then just uncheck "Time to display list of operating system". Apply
the changes.
Hope this help, let us know!