Hello Marcos Vinicius,
If you lost the serial number, go to
https://www.bandicam.com/buy/ and enter your purchasing email address at the license check section.
Your license will be sent to your email again.
https://www.bandicam.com/faqs/bandicam_ ... on_policy/
If you can't access your email, please send your receipt to
bandicam@bandicam.com.
Thank you.