Hi Rainer. I too have this same issue with my Dell Latitude D630...
Here is the underlying issue:
I have an Intel 4965AGN wireless card.
Microsoft lists this card as compatible for Windows 8 and Windows 8.1 and claims that there will be no issues using it when one runs the Microsoft Windows 8.1 upgrade assistant downloaded directly from the Microsoft website. Microsoft is the provider
of the driver for both 8 and 8.1 which is the one I have and MS offers no newer driver than the one from 2010.
According to Intel, this device is no longer supported. As such, Intel does not provide drivers for this card for either Windows 8 or 8.1 and refers the user back to Microsoft for support.
Unfortunately, the driver that Microsoft has provided for use with Windows 8.1 is actually incompatible with Windows 8.1 and is causing the BSODs.
I found the cure: removed the Intel 4965AGN card and replaced it with a newer card that is supported directly by the vendor.
Had MS's upgrade assistant flagged this hardware item as being incompatible, I never, and I mean never, would have upgraded to 8.1 (Windows 8 worked perfectly - I never had an issue!)
I blame Microsoft for causing this issue and then passing the buck back over to Intel.