xoops 2.0.5

i have installed it
database created
all my modules installed
everything OK

in the middle of the proces i screw up something and i want to install my XOOPS again but i dont want to waste my time and i use my old database

i have installed it again
all my modules installed
everything ok BUT:

whan i tryied to copy an old database in sql to replace the new one it want let me log in as administrator.

i repeat: site looks fine, all my modules OK, PERFECT - even when i log in as administrator it says on the top of the page

thank you for logging in administrator - but i'm not logged in - it just kik me back to the front page

i tryed to mess up with xoops_users.MYI;*.frm;*.myd but i screw it up worse

what i did wrong and how i can fix it ?

Amazing

I have copied it, it works, but soonest I delete cookies it want let me log in again

HELP! - Or I’ll delete the database and do all work again.