doing a re-confirm

Ran a migration of 1.5 to 2.5 and 1.7- 1.8 cb

i have ran a mysql command to change all 1 to 0 in the comfirmed feild of cb (due to many spam accounts)
and some times when an e-mail is sent there is no confirm link or the link looks like this

http://site/index.php?option=com_comprofiler&task=confirm&confirmcode=&Itemid=128

no confirm code at all!
what do i need to do?

any ideas. or even how to remove inactive accounts from 6 months+. something to lighten my DB of the some 1000(s) of users