You're off topic for this forum, which is dedicated to Windows Live OneCare. You may want to try the Microsoft Public newsgroups here: http://www.microsoft.com/communities/newsgroups/list/en-us/default.aspx
However, it sounds like you installed a second copy of Windows without doing a complete disk format first. You may want to start over, but this time select the option to perform a fresh install and instruct Vista to delete the existing system partition and make a new one. If you need help with this, I recommend contacting the PC manufacturer for help.
-steve