Error message & Video editing support

I'm getting error message NDA Error - Failed to load application configuration data from "core.hp.main/application.xml". I see the start up and can disable it but how do I keep a normal boot startup AND eliminate this annoyance. Also, I'm getting the end process error for explorer.exe when shutting down or restarting.
I'm looking through forums and what not to find good information on burning movies/music software and codecs. I have issues, sometimes, with Nero and Roxio with video editing; pc locks up. I know I shouldn't be using both but even after uninstalling one, the other worked no better. I like to do edits of home movies and dvds. Any advice there?
WinXP home-SP2 AMD Athlon 64 3500 @ 1.77 ghz 448 mb. Speed changes, was 1.97 ghz which still seems slower than it should be.