How to De-activate license without being online. (Computer infected with Malware)

Hello,

My computer has been infected with Malware, and shutdown since. I'd like to de-activate the license so that I may reinstall after a reformat & reload of the operating system.  Would that require me to call in?  Trying to see if this can be done someway after Avid support hours (1-800-800-2843).

Thank you,

Irwin