[support] manually disable custom block

OK ... I've managed to implement a custom block that hoses my login block (amazing what happens when you forget to close your form tag! ... <smacks self over head>. I need to disable it from the back end. I'm looking at the blocks table, but don't see a way. Any one have an idea on this one? And of course I'm supposed to orient a few people to putting content into the system in a little bit .. .ugggh! TIA, Jason