I have a Dell tower computer I just moved to a new house. It does not have any native wireless adapter, instead using a USB "QR Computers Inc 802.IIN". It will not connect to my house's main wireless, either cycling indefinitely or returning an "activation of network connection error" response.
HOWEVER, it will connect to any hotspot generated by my phones, other computers, etc. All my other phones, computers, etc will also connect to the wifi just fine. The problem is only this one computer with this one wifi network -- any other pairing of devices and networks works.