Workgroup Computer Not Accessible

Hi all, I've been searching around the forum and found some similar threads, I've tried out the suggestion, but still couldn't solve my problem. This is my problem. I create a workgroup for my LAN, connecting 3 computers:

1) COM1 - Desktop computer with Windows XP Home
2) COM2 - Desktop computer with Windows XP Pro
3) COM3 - Laptop computer with Windows XP Pro (Wireless connection)

- Ping is successful among all the 3 computers.
- ALL computers can see ALL workgroup computers in My Network Places
- NWLink IPX/SPX/NetBIOS Compatible Transport Protocol is enabled in all computers.
- TCP/IP > WINS > NetBIOS over TCP/IP is enabled in all computers too.
- Use Simple File Sharing (Recommended) is enabled in COM2 and COM3. But can't find this option in COM1 (Win XP Home).

But, my problem is:-
- COM1 can access to all shared docs among ALL computers.
- COM2 and COM3 can access to shared docs among one another, but can't access shared docs from COM1.

Whenever COM2 or COM3 want to access the shared docs from COM1, I got the error message of "\\COM1 is not accessible. You might not have permission to use the network resource. Contact the administrator of the server to find out if you have access permissions. Access is denied. "

Anyone can give suggestion on solving the above mentioned problem?
I can give more information if needed.
Thanks in advance.

 

Check.

For XP home.
Start "“ Control Panel "“ Network Connections "“ Local Area Connection "“ Properties "“
(check mark), File and Printer Sharing for Microsoft Networks

Hope that does it.