Vista - Ping - not working on laptop

I have a home network connecting through a Linksys 4-Port Router. I
connect my Desktop and my Laptop on the network to share Internet and
files and printers. I have WinXP (no SP3) on the desktop and Vista
(no SP1) on the laptop. I have my harddrive partitioned into 3 and
share the "E" drive with the laptop. This has worked fine for a long
time, but lately, I cannot access the desktop "E" drive from the
laptop.

To check to see if the two machines were seeing each other, I "ping"
the laptop from the desktop and get timeouts. I "ping" the desktop
from the laptop - and the ping doesn't do anything - just sits there
with the ping command and takes no action after hitting enter.

I'm not sure whatelse to provide you all to get some assistance on
this problem, but if anyone has any advice, I would appreciate it. If
you need more information, let me know and I will pass it on.

Thanks
Charlie
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Charliec