Well, Windows programs normally don't "hate to open directories with much files" or something like that. This is no different for editors. I also don't think that items on your desktop affect file opening, unless you open the desktop folder with a program.

I'm afraid I can't give you a good advice, but maybe you can find help on a Windows forum. Check for some resident programs on your PC that might affect file opening, like some "directory history" programs. I can also imagine that a damage of the hard disk directory structure could lead to such problems - so run a hard disk check.

Otherwise, try to find out whether it's totally random or only happens with certain folders or files. This might also give you a hint where to look for the problem.