I replaced notepad on my system with edit pad, it's fast, simple and doesn't try to do too much but what it does do is better than Notepad by far. http://www.editpadlite.com/

A great set of tools for finding out what is going on in your system can be found at sysinternals.com, two of my favorites in particular FileMon, Handle. I use these sometimes to find out what weird stuff is happening with files.