I love my laptop/handheld GPS setup. I use Nobeltec. The older versions are widely available free. I am also concerned about the "blue screen" although in several years of use it has not happened. Of course my backup is to use the paper charts that I always keep handy. I would either plot visual fixes or GPS positions. Too easy really. The laptop is just another tool in my bag.
There is a tide in the affairs of men,
Which, taken at the flood, leads on to fortune;
Omitted, all the voyage of their life
Is bound in shallows and in miseries.
Shakespeare, Julius Caesar IV, iii, 217