RE-INSTALLING A FRESH COPY OF WINDOWS XP WITHOUT LOOSING MY WORK

In recent time i have been facing and still facing the problem of loosing my work on drive C i.e the default drive which houses windows. This comes when for example, a virus corrupts one of the files and the computer fails to boot, so in the process it necessitates a fresh copy of XP, but then i have my valuable work i don’t want to loose.

My concern is how can i do it without loosing my work and at the same time intalled a fresh copy of XP.

Thanks