If you are secure enough to try you can remove one of the OS boot lines (if you want to remove XP setup and just have your original Millenium OS at boot time).
You have to make sure under tools>folder options> you have turned on <show all files> and <show system files>.
Then, using My Computer Icon, go to file called boot.ini and edit it with Notepad, by right clicking on it and then <open with> select Notepad.
Look for 2 lines that this file is using when it boots windows.
You should have 1 line for each (OS-XP Setup and Millenium).
The XP setup line is the first line if that is showing first.
Delete the line that is there for <xp setup> or just change the order of them with cut and paste so the right one comes up first.
BE VERY CAREFUL! IF YOU DONT FEEL YOU CAN DO THIS OR IF THAT BOOT.INI DOES NOT SHOW BOTH STARTING OSs - JUST CANCEL OUT AND SELECT IT EACH TIME.