I replaced my computer and am trying to reinstall Vegas Pro 18 on my new computer. The serial number is already registered and error code 14 appears. Please help me to solve it.
If the program says that the serial number is already registered to a different e-mail address (error 24, not 14), you need to make sure to use the same e-mail address like you did during the previous installation. If you want to change your e-mail address you need to do it in your customer account at https://www.magix.com/int/support/my-service-center/
In addition to what @SP. has told you please be aware these are NOT the forums for the Magix Vegas range of products. Please read this pinned post and follow the advice given there.