Getting 360 back to normal media sharing...

I have Windows Vista Home Premium, and I want to get my Xbox 360 to stream
media the regular way, without Media Center. Because with Media Center, I
can't play my music while I'm playing a game. If you know how to do this,
please let me know.

Also, my 360 is not letting me select a PC. I go to Pictures/Videos/Music
and select Computer, and then wants to Test Connection for PC, but when it is
testing, it fails at Select Computer.

My laptop is wireless and is on a WPA2 Security type with TKIP Encryption.
My 360 is a direct connection to the router (which is connected to the
modem). I shouldn't have to enter my Security Key, right?

Anyways, please help me out..

Anyone got any suggestions. This is aggrivatating.