Laptop Clients with intermittent network/web access

Hello,

My setup:
PowerEdge Server, Enterasys Acess points, built in Dell wireless cards, Dell 
Inspiron laptops (x4), Cable internet, 2 story office building.

Problem:
When connecting wirelessly to the network the 4 latest laptop additions are 
having an intermittent problem connecting to the server (specifically network 
shares) and browsing the internet. This only happens in wireless mode and 
only with the new laptops. The other 20 laptops (older Dell inpirons) connect 
with no issues. 

The new laptops will receive an ip address and all the correct 
configurations (DNS, Gateway etc...varified with ipconfig) and will 
authenticate and log into the domain (no error msg logging in) but will 
sometimes be unable to ping computers (including the gateway and server), 
connect to shares, or go online. They are setup the same as the other laptops 
that connect and they work perfectly when plugged into a wired connection.

Strange thing is sometimes we can coax the laptops to work by:

1. logging in as local administrator
2. Browsing network neighborhood (sometimes the other computers show 
up...sometimes not)
3. clicking on IE

after the exact above steps the laptops will 8 out of 10 times work 
correctly and then we can log into the domain and have file/web access until 
the next reboot!
If we try the same steps wile logged into the domain...nothing...it only 
works with local admin!

I am stumped by this one...anyone have clues?