Removing Dual Boot Linux or Vista with is tricky because of their Bootloders. Many times I receive SOS message regarding it.
Situation: You have installed Linux or Vista with windows XP and letter need to uninstall it. Or (in most of case) you already formatted that VISTA/Linux partition and unable to Boot XP.
What You Need: Bootable XP CD
Boot Computer from CD Driver (Make CD Driver first bootable device of use BIOS boot menu)
When your computer start from XP CD it will prompt for Pres any Key to Boot from CD .., Press Enter
After some time you will see a screen similar to this
Wait for some time until you see a screen similar to this
If it is asking for “Which windows installation you want to log?” provide 1/2/3 according to shown in list above (if not sure type 1) and press enter. Now you have to type your Administrator Password to be able to use the Recovery Console. If forgotten than you can try these steps with Windows 2000 bootable CD instead for XP. Read this article to break XP Administrator password: http://tec-articles.blogspot.com/2007/11/forgot-windows-xp-administrator.html
Now you can see a typical DOS command
Type FIXMBR at command prompt, if asked for conformation press Y
Type FIXBOOT at command prompt, if asked for conformation press Y
You are done, take the Windows XP CD out of drive and restart your computer .