On more than one occasion, I've been remote to a machine and needed to pull the service tag.  Dell has a mechanism on their site which can get that information for you but I seem to recall it only works when you're physically on the machine and not accessing it through an RDP connection.

Since I access almost every machine while being remote, you can see how that poses a problem.

Seems I've encountered this issue several times over the last few weeks with Windows Server 2012.  I attempt to install updates and the progress bar will hang, essentially stalling out.  I cancel, I restart but I end up in the same place.

When I first saw this issue, I read something about setting updates to install automatically in the middle of the night which managed to get the updates installed but it doesn't actually solve the problem.

While attempting to install .NET Framework 3.5 from Add Roles and Features fails with the error:  "The source files could not be found".  Attempting to install from the .NET 3.5 Framework install fails pointing you back to Add Roles and Features.