D600 unable to connect to a Wireless network

For some reason, I cannot get my D600 to connect to my wireless network.  I've tried several machines so far, under different scenarios.  Each machine has XP sp3 installed.  One has the Dell 1350 wireless mini pci card installed, the others has the Intel 2100 wireless installed.  both are listed in Devmgt w/no yellow error marks.. both appears to be working fine.. all diagnostics says it's working okay.  On the Dell 1350, I setup all the appropriate drivers for the PC (updated bios, Chipset, 570x Broadcom, video, audio)... no yellow marks in Devmgr, but it just won't connect.. tried connecting using the Dell Wireless WLAN utility, but my network gets a big X over it.  If I try using Windows, to connect, it won't even display any avail networks.  If I add an ad hoc connection, it connects fine, but I still cannot get to the Internet.    I have 2 HP laptop and 4 older Dells connected via pmcia cards and one connected via a usb adapter, so I have experience in setting up wireless connections.... Any advice you have would be greatly appreciated, as I have spent much too much time on this.  My company will be donating 20 laptop to a local school here in Pittsburgh.  Would be nice if the teachers could use wireless.  If I don't get it configured for them, I can't imagine they would be able to themselves.  So, far I've tried 3 of the 20 and have gotten nowhere for this.   Note:  Already went thru the Dell Wireless Troubleshooting...