On occasion MSCONFIG does not appear in the list that comes up when chosing an item from the "RUN" list (click start/click run) - at this point MSCONFIG normally appears in the "open" box. At times it disappears. I type it in and MSCONFIG runs normally (I use it to cleanup the startup list)
I don't mind retying it, just want to know what's causing it to disappear.
If you cleanup your temp files, that could be why.
FYI, msconfig isn't the best way to modify startup programs. It will work, but if you disable the startup option in the program itself, msconfig won't have to block it. There is also a startup folder that may contain programs you don't want starting up. You can clean out this folder, and those programs won't start up with windows.