Network Issues

Since 5728, I have had some major network problems with Vista. I'm
currently using 5744 (RC2) and am running into the same problems. I have
already reported them. Can anyone help?

Living Room Computer (Computer 1): Windows XP Home SP2
My Computer (Computer 2): Windows Vista Ultimate 32-bit 5744 (RC2)
Office Computer (Computer 3): Windows XP Home SP2

Issue #1: When I copy a file onto another computer's network from my
computer, Vista shows the 'calculating time remaining' box and it stalls
out. It acts like it's trying to copy it, but it just sits there on
'calculating time remaining'. If I try to cancel it, the explorer will
freeze up and have to be ended.

Issue #2: When I try to access a file on my computer from another computer,
let's say, Computer 1, explorer freezes up on the XP computer, and the file
will not open. After about two minutes of waiting, explorer becomes
responsive again and it says that it lost the connection to my computer on
the network. When I get back on my computer, Vista completely loses my
Internet connection until I restart my computer.

I really hope they don't release Vista in this condition. Any help? Thanks
in advance.