Drain on battery -- 2 days to go dead -- Taken out all fuses -- still a drain -- disconnected the alternator -- drain still exist -- any suggestions?

I put a test light in series on the negative cable the light is on, indicating a drain. The first fuse I pulled was the dome /cabin light fuse, so I could leave the doors open while doing the checks.

I was told to- re hook up everything and still see if there was a drain. Because everytime I turn the key to the on position the computer will take 30 mintes to shut down. Is that true?

Thanks for any suggestions!!