Can't contact with other computers in the network

I have a desktop(LAN) and a laptop(WLAN) under a route and they all install NIS 2010 ver. 17.5.0.127. Sometimes I find the laptop can't access the shared folder in the desktop after it is just waken up from STAND-BY or the laptop is running for a long time. In this case, the shortcut list of all shared folders in the desktop disappears in the "network neighbourhood".

 

I type the desktop IP(\\169. 181.......) in the address inputbox directly, but it still doesn't connect.

 

Only after I refresh the Wireless connection on the laptop, then the desktop can be accessed, but the shortcut list isn't back.

 

Finally, I run "net view \\169.181......" in the command window, then the shortcut list of all shared folder in the desktop is available in "network neighbourhood".

 

 

Windows XP SP3 - IE8 - NIS2010 ver. 17.5.0. 127