how do you Deauthorize a dead computer for itunes

Hey there idonotexistatall,

We understand you're asking how to deauthorize a computer that does not work in iTunes. We'll be happy to help.

Since you're unable to use the computer to select the deauthorize option, you'll need to deauthorize all computers. Afterwards, authorize the computers that are working again.

Reference the steps from the section "If you run out of authorizations, deauthorize all" here: Authorize or deauthorize your computer for iTunes Store purchases

Cheers!