hello folks, i recently installed my new windows 7 pro in 64bits, after i started to install my zbrush 4, i realised that i forgot to desactivate my license before to reactivate it… i wonder how i should do ? i already posted a ticket support for it. but i noticed it took too long so, i decided to share the embarrassing problem… :o ah yes, my name is **********.
thx for the help ! 
Just do a new web activation. If you’re out of activations you’ll get a message saying so and there will be a button to “View Activation History”. Click that button. In the list you’ll see, check off the activation that was lost and submit the form. This creates a Support ticket with the necessary info to fix the serial number and set it back to an accurate list again.
allright ! i will do it soon i will edit my post if it work
ok, now it work like a charm ! next time, i will try to not forget to desactivate it ^^;
anyway, thank you Lord Aurick