NovaLou, sorry i didnt' see your posting earlier. Using the MSConfig utility only removes applications from starting when booting up. It does NOT apply to your situation.
Based on your posting i'm gonna assume you're not very computer literate - and thus you probably installed the 2nd XP on the same partition as the first one. That's fine if you did. If so, simply look on the root drive of C:\ and look for a file called "Boot.ini" . It is a system file so it will probably be hidden when you try to view it under Explorer, so you can turn that feature off by going into Tools menu, Foler options, then click on the view tab to change that.
Once you've located the file, you can edit it w/ a simple text editor like Windows Notepad. Copy the contents of that file here and i'll guide you further.