Dried out roots are different from bad roots. Does it have firm roots that soak up water, changing from white to greenish, when you soak them? If so, then it has viable roots. If the roots are not firm, but instead are brown, soft and papery, the roots are bad. Firm roots that are brownish may, or may not, be OK.
I'll share some photos of one of my orchids in recovery. (BTW, to be fair, this plant is in trouble not because the plant I received from Carter & Holmes was bad; I made some mistakes in caring for it). If I have a salvageable plant whose roots are not doing well, I clean the plant and just hang it up somewhere in the shade through the summer to see what roots go bad and which start growing again:
and
The brown root looks pretty bad. However, the lower two green "pointers" indicate a live root an root tip coming from the brown root.
The point is, assume that firm brown roots are alive and treat them like any other root.