As in, any student, Deirdre?
I'd certainly be interested to hear the answers for that; at present, we send out instructions to students - and have tried sending them CDs with screen captures etc.
Most students are able to work it out, but there are always going to be students who have problems - and diagnosing the cause of the problem at a distance is difficult.
I'm a lecturer (faculty), and so I also have to ask at what point we have to hand over to technical staff (e.g. to help students sort out what seems to be a firewall problem), and at what point do we have to stop - as clearly our technical staff can't diagnose every single problem - and it may be something that just won't run on the student PC, due to other restrictions in place.
That said, the only students that we have who really run into problems are those that are using work place computers, and it is their work place restrictions that are the barrier.
For students using assistive technology and/ or just ensuring that their computers are set up optimally for them, it's yet another issue.
(I'm wimping out of that for a new course we're setting up - it's going to be blended learning, and the students will come to the University right at the start. WE'll encourage them to bring their laptops, so that they can learn to access the software on a familiar machine. For those that haven't got them, we can at least familiarise them with software on our computers & hope that their own machines aren't too different....)