It is very important to try to get the best 'fit' between the worker and his/her environment - for more information on Ergonomics, see this page. As a first step to help identify whether professional advice (eg an ergonomist) is needed, use the Ergonomic WorkStation Checklist
Another useful document [pdf] is Participative Ergonomics - a Guide.
More information on workstations, computers, and more can be found in the Workplace and Amenities FAQs section of the site.
Last amended January 2015