Don´t know how to deactivate my license in order to transfer it to another computer

I have installed HTML Executable ver 4.9 on Windows on 2 of my PCs. A couple days ago, I had to format one of the computers and lost the installation. I tried to reinstall HTML Executable and got the message “exceeded number os installation”. Since I can´t install it again, I´m trying to deactivate the remaining installation in order to transfer it to the recently formated computer, but I just don´t know how to do it. I can´t find a button or link… nothing. Can I get help to DEACTIVATE and then REACTIVATE my activation code that I’ve been used before?

See this page:
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You can also contact us by email so that we check your account and deactivate manually.