cant install v1.6 cause v1.6 is already installed

so i am stuck, i have deleted and reinstalled the files, but when running the install programas an upgrade it stops at part 3 with a version 1.6 already installed error, even though it isnt installed. i even tried the new install but it stopped at the same place with a sorry its not a new install. is there a place in the database that stores the version number and it needs to be removed?  thanks

never mind this is answered in upgrades, and i did find an old connectionstrings.config string for v1.5 and it worked, thanks