My Windows XP Pro started getting very slow and eventually all apps refused to open. So... I reinstalled Windows XP Pro. During the install process, it claimed to delete the previous Windows XP install. However, now when I start my computer, it presents me with a black screen and simple white letters asking me to choose which Windows XP Professional I want to open. The top choice works, the second doesn't. How can I make my computer think I have only one Windows XP? Thx.