Three problems with Hoary

[Ben Novack]

First, the major problem:

Mplayer doesn't work with Firefox. If I open a media file within
Firefox, it wants to user Mplayer, but the Mplayer controls are one
big black blob, and it never does anything. Yesterday I tried to view
a video feed with it; the video panel was just black.

Now for the minor ones:

FIrefox has a new habit: Whenever it closes, it stays open for about a
second while a message box informs me that it's not responding; then
it closes. It didn't do that in the past, but I can't pinpoint exactly
when it started, so I can't tell if installing some new packages might
have done something.

Finally, I have a couple of items on my desktop - files I haven't
sorted, and a mounted external hard drive. If I mount another drive -
say, by inserting a CD - the icon appears *over* the first icon on the
desktop. Is there a way I can get the icons to auto-clean up?

Many thanks in advance if anyone can offer some help.

---Ben