AbilityNet provides free information and advice, individual assessment of technology needs, the supply of assistive technology with free support, a programme of awareness education, and consultancy for employers on system and workstation adaptations.

Their website contains excellent information on how to make your PC more accessible (follow the "my computer my way!" link below).

www.abilitynet.org.uk  (main site)

my computer my way!   (PC accessibility information)