"I am sure that I have installed the new windows at the right drive "
From that statement, do you have more than one hard drive? If yes, why do you have more than one Windows installed? Have you looked for the other installation in explorer? Go to "My computer" and look in there to see if it shows more than one hard drive. Then look for a "Windows" folder. If you have more than one hard drive shown and each has a "Windows" folder, then it could be both installs are still there. But why do you need more than one Windows installed?
I am having some problem with operating systems. I have 2 windows previously (both windows xp pro) but after I reformat 1 of the windows, the another 1 have lost. The main problem is the pc never ask me to choose any windows in the main menu before logging into any windows so I can only use 1 windows currently and also I am sure that I have installed the new windows at the right drive so suppose the lost windows is still working but the only problem is the pc never ask to select which windows to login in the main menu. Hope anyone can help