I read your problems from the previous 2 threads, and it smells like a corrupt registry. Concerning the installation of Win over Win: bah! Use the PowerJoe method, or boot into DOS and del Windows. Then, do the setup.exe. You don't need to reformat C, and you won't lose your files. But, you will have to reload the .exe programs from your CD's and some settings and preferences.
If you have folders on your desktop, just make a new folder on C named DesktopTwo and copy to it because Win will replace your desktop completely. IMHO!