Errors in your registry are one of the common causes for incorrect file associations on your windows system. It is highly recommended that you check your registry for file association errors (will also check for any other registry errors).
The LOGONXP file type is primarily associated with 'LogonStudio' by Stardock Corporation, Inc..
LogonStudio is a free program that allows users to change their Windows XP logon screens.
It comes with several logon screens to choose from, along with thousands that are available online from Web sites, such as WinCustomize.com.
Cannot access LOGONXP files on windows?
When windows gives you an error message saying that it "Cannot open LOGONXP files", this means either:
A. You need to indentify a program that can open the file B. Or your registry may be damaged
RECOMMENDED:
In both cases it is strongly recommended that you run a free scan for registry errors.