Network Shares and Remote Desktop

I have three machines, two desktops and a laptop.

The laptop and one of the desktops (64bit) are running Windows Vista RC1.

The remaining 32bit desktop is running Windows XP Pro SP2.

They are all connected to a wired network, except the laptop (Workgroup not
domain).

I have network shares on all machines and remote desktops enabled as well.

When using my laptop I can connect to the shares on my Vista desktop but not
my XP desktop. I also can remote control my Vista Desktop but not my XP
desktop.

Now from my Vista desktop I can remote control all machines and connect to
all shares.

From my XP desktop I can also remote control all machines and connect to all
shares.

I have the same logon account including password for each machine and they
all have admin rights.

I have adjusted every setting that I know of on my laptop and my XP desktop
but I cannot connect to the desktop from my laptop.

When I connect through remote desktop I connect but only get a blank black
screen, which I have read all posts on this and nothing works including
reducing the MTU and disabling bitmap caching.

I have simple sharing disabled on all machines and I have disabled the
firewall on all machines, I have adjusted the authentication within
Secpol.msc but this does not help either.

Does anyone have any ideas? TIA.