basically the only way I can see at having a quick look at the DNN3/4 code is to mod the PortalSecurity.vb code to bypass the actual database check on the password - this may or may not work. I think you can change the email address directly in the database using enterprise manager or the like. This most probably would be the best approach - change it to yours then get a password reminder sent to your email address for the host id.

I don't have much to do with the code of V3/4 but I am sure that some one out there can point you in the best way to edit the database to change the email - however this would be a direct breech of DNN security and any one that suggests the solution would need to some how certify that you actually own the site. I would assume that if you have access to the database userid and password then you could say you own the site.

if you have not added much content to the site then the fastest way is to reinstall the site.