Still though, you are doing that on your own desktop. What you are asking is changing this on someone elses desktop. Security issues would tell you that it won't be possible, just like with
Java applet you can't read or write to a client's files without first getting explicit permission.
But hey, I could be wrong. If you find out how to do this, I would love to see it, even if I never use it. Make sure you post it if you find an answer.