Desktop A wired-sharing "D" and "E" drive (THEDELL)
Desktop B wireless-sharing "D" drive (THEHP)
Laptop wireless (COMPAQ)

All connected by Linksys WRT54GC.
All firewalls disabled on PC's-firewall enabled on router
All in workgroup called "HOUSE"
All running up to date "Avast" antivirus
All running remote access program called RealVNC
All can reach internet with no problems
All have ENABLE NetBIOS over TCP/IP turned on
All running Windows XP Home

Here is the problem, workgroup HOUSE cannot be found on laptop after booting from cold start or standby(therefore Desktop A shared drives cannot be accessed).

If I ping desktop A with the computer name(THEDELL), it cannot be found.
If I ping desktop A with the IP ADDRESS, it is found. Then re-pinging the name will work.

OR

If I use RealVNC to access desktop A from the laptop(just open up the access window then close it), then I can access the shared drives.

After successful pinging or using RealVNC, shared drives on Desktop A can be accessed.

After a period of time (undetermined), the shared drive access goes away and I have to do one of the two processes to access the shared drives again. Rebooting does not help!!

Does anyone have any idea what could be causing this?1. The laptop needs to be able to locate the sharing computer. Try one or more of the following:
a. Ensure "Computer Browser" service running on at least one of the workgroup computers.
b. Create "lmhosts" file on laptop (if static IP addresses) in the %SYSTEMROOT%\SYSTEM32\DRIVERS\ETC directory to associate NetBIOS names to IP addresses.
c. Possibly use IP address (if permitted and static) instead of NetBIOS name when mapped network drive is defined on the laptop. May want to check "Reconnect at LOGON" box when network drive is defined.

2. Computer Browser is the METHOD normally used.

3. Reference(s).
Why Can't I See My Computer on the Network?

Troubleshooting File and Printer Sharing in Microsoft Windows XP
File and Printer Sharing with Microsoft Windows

Troubleshooting Computer Browsing on SOHO Networks with Microsoft Windows
Computer Browsing for SOHO Networks with Microsoft Windows