Wireless NO - Wired Yes

Hello...

I have two computers. The Windows XP Professional is wired directly to my 5
port SpeedTouch 780 10/100mb switch. The Vista Home Premium is a laptop
and is wireless connected to the same SpeedTouch 780 DSL Router.

Both computers can see each other on the network. I can browse all the
allowed folders on the Sony Vaio Vista Machine

**** but I cannot browse the folders on the XP machine from the Vista
machine. *** I CAN open the folders but I cannot copy files and if there are
a lot of folders, VISTA will sit there and hang while the progress bar
progresses and finally the Vista machine will kick back an error message
saying that Windows Explorer has quit with no explanation.

HOWEVER, IF I disconnect the Vista wireless connection, and I cable it, to
the same SpeedTouch 780 switch, THEN I CAN browse my folders on the XP
machine and EVERYTHING works like it is supposed to.

I have turned off the firewall and disabled anti virus on both machines.

What can I do to troubleshoot this problem?

And DOES ANYONE have a tech support phone number for SpeedTouch 780 DSL
Routers?

Dale