Vista - unable to see windows XP network drives from my vista computers

hello
I have a windows XP and a Windows Vista computers, I'm able to go into the internet from both computers. From my windows XP computer I'm able to see and map the extra hard I have on the vista computer, and as well I'm able to ping the Vista computer from my XP; however, from the Vista computer I can't ping the XP computer nor see the extra drives I have in it. who can help me to solve this problem. I've tried many ways to do it but I haven't been successfull.
can somebody help me please
I need to solve this problem ASAP.

To share files or a printer from XP computers, follow these procedures:~


1. Download and install the Link Layer Topology Discovery (LLTD) responder:~

http://www.microsoft.com/downloads/d...displaylang=en

Read the instructions!



2. Check these out as well...

Windows Technet:~

File and Printer Sharing in Windows Vista

Most Valuable Proffesional:~

How to share files or a folder in Vista


3. Don't forget to configure (Input ip addresses in subnetworks) your Firewall to accept sharing from other computers.If you have Kaspersky check this below:~

Kaspersky Blocks My Network


I hope this solves your problem...

I tried step one and I received this message
Setup has detected that the service park version of this system is newer than the update you are applying.
There is no need to install this update.