Xbox 360 will not recognize external hard drives on pc

I have my Xbox 360 connected to my PC wirelessly. I had it set up so that I
could view my vieos, etc., that were on my PC with no problems. Most are on
an external drive. A week or so ago I shut off my external drives to let
everything cool down, and now my 360 won't recognize the external drives. It
still gives me the option for any files on my internal HD, but the external
ones do not show up in either the "Videos" section, or "Media Center". They
are all there, however, if I go into Windows Media Player or Media Center on
my PC.

Hi All users,

Just want to know if anybody else have had the same problems as I have with
my dvd drive.
Sometimes it is not recognized anfd I have to change the behavior in Vista
on what to do when I insert a CD into
the drive e.g ask me avery time and that kind of stuff.
Sometimes it works to change the preferences and sometimes not, it workede
ok when I run XP on the same computer (laptop)
by the way it is a lenevo T61,
I f anybody else have had a similar problem please let me know.
Regards,
Conny
I am Swedish so please excuse any bad language in my mail.