ok- so i downloaded an iso, checked its hash, removed the ei.cfg and then install Home Premium (the version that originally came installed). once it got all installed i went to activate w/ my COA key and was still told it was not valid. le sigh. guess i will need to do it the less than legal way. thanks windows for making it impossible for me to reinstall the OS i actually legally purchased.
update- used the Daz Loader to 'load' with my COA key. then did phone activation... and well it seems to have successfully activated.