3 laptops with Windows 7 Ult reinstalled won't reconnect to network.

I recently installed a new version of Windows 7 Ult. onto three computers. two were Fujitsu, one was Dell, previously they had Windows 7 Pro. One has given me no issues, the other Fujitsu connected to the every network fine, but then wouldn't connect to the office network. After bringing it home, and connecting it to my network, it said there was a problem and the diagnostic fixed it.

The Dell reacted the same way, connected to everything fine, then when it goto the office it connected fine, but then after it was brought home, when it went back to the office, it didn't connect. At this point, the only computer that is causing problems is the Dell, it says it is connected, but the browser isn't working at the office. It works fine at any home network.

Any ideas?