Thank you for speedy responses.
I have been running it on a compaq desktop for around 3 months working fine on a daily basis. then suddenly today i get the error message "you need to format the disc in drive K before you can use it". I tried it on my old desktop and the same message comes up. I have had the HD for around 2 years with no problems.
I am extremely sorry but not sure how to take screen shots. :(