Cannot Get Past Setup Initial Install Screen

been a while since i last used cscart, my first store was 2.1... so ive unpacked 4.7.2, typed in my web address to get to the first screen, but then when i press install, nothing happens.

my browser address changes and adds another install word ie below

i know it either must be permissions or one of my config files perhaps but im not sure what to change

any help would be appreciated