doing a fresh wordpress install over an old wordpress blog.

hi there,
my friend would like me to show him how to build a new website using wordpress and i’ve recommended that he buys a licence so that he can do it via your enfold theme.

he has a basic old html / css website here at: http://www.ifsmotivationaldefence.co.uk/

but it does have a basic wordpress blog installed here: http://www.ifsmotivationaldefence.co.uk/blog/

i’ve propsed just deleting all of the old page given it looks a little rusty and out of date now, i told them they can use this ‘under construction’ plug in while the new site is being built: http://wordpress.org/plugins/ultimate-coming-soon-page/

however, i’ve never built a new wordpress site to replace an existing wordpress site. will there be any problems if i just delete everything from their web hosting server (including their existing wordpress site) using ftp and do a fresh reinstall wordpress and then start building from scratch? is there anything i should be aware of that i haven’t thought of in respect to any of this?

thanks,
paul