Need to deactivate my license - can't open Studio

Because of problems with a plugin, I can't open my Studio SR1 CU4 installation. Nor can I use the CU5 beta because it refuses to accept my normal password (which I used here, for instance, without problem) nor will it send me the promised email to reset it.

So I need to transfer the license to another computer and therefore deactivet the currently active licens.

Thanks in advance!

Mats Linder