The MATRIXx License Server is part of the MATRIXx License Manager installation and is the utility that you use to manage the MATRIXx licenses, especially if you are using floating licenses. As of MATRIXx 7.1 the LM Tools utility is used instead, and it can be accessed from the MATRIXx category on the Start Menu. I would not recommend removing the MATRIXx License Server from the Control Panel, but here is a KB from the Microsoft website that gives instructions:
http://support.microsoft.com/default.aspx?scid=kb;en-us;261241&sd=tech
It mentions Windows 2000, but the steps are very similar for Windows XP. Once removed you will not be able to configure the license manager until you unhide it again.
Carl L
National Instruments
www.ni.com/matrixx